Defending champion Jannik Sinner defeats Alexander Zverev in straight sets to qualify for semi-finals at 2025 Nitto ATP Finals in Turin

Jannik Sinner booked his spot in the 2025 Nitto ATP Finals semi-finals with a convincing victory over Alexander Zverev.

The reigning champion extended his winning streak on indoor hard courts to 28 matches courtesy of a 6-4 6-3 success in one hour and 37 minutes.

The win coupled with Felix Auger-Aliassime’s triumph over Ben Shelton means the Italian progresses from the Bjorn Borg Group with a match to spare, while Zverev will have to fight it out with the Canadian to join him in the last four.

Speaking on court following his victory, Sinner said: "It was very, very competitive - a very close match.

"I felt like I was serving very well in important moments. I tried to play the best tennis possible when it mattered and fortunately today it went my way.

"We both changed a little bit tactically, so I felt like we were both trying to hit quite fast, quite flat. I’m quite happy with how I returned his serve; very difficult, it's one of the best serves in the game.

"The group I’m in, with Sascha [Zverev], with Ben [Shelton], it’s very difficult to return the serves, but I’m very happy and let’s see what’s coming.

"I'm very excited to be in the semis."

It was Zverev who made the brighter start, probing for an instant break but seeing two opportunities snuffed out as Sinner needed four aces to help him through a tough opening game.

The Italian grew more consistent as a serve-dominated contest developed and he broke at 5-4 on a third set point to seal the opener in 47 minutes.

Sinner survived a triple break point early in the second stanza and then fought off another in the fifth game as Zverev pressed for a way back into the match.

There was a sense of inevitability about Sinner making him pay again, and the home favourite duly broke for a 4-2 lead courtesy of a sumptuous drop shot.

Zverev did have the opportunity to break back, but Sinner came up clutch to consolidate and eventually served it out on his first match point to stay on track in his defence of the title.

The reigning champion is back in the semi-finals!

Zverev tries to up the ante when he shunts a backhand down the line to punish a poor dropper but a drive volley puts Jannik in charge at 30-15 and a big backhand down the line clocks up two match points.

The Italian only needs one as another hefty first serve doesn’t come back to ensure he progresses after one hour and 37 minutes.

Zverev marauds through a hold to 15 with Sinner seemingly content to get it out of the way.

The serve-out question is posed and it’s over to Jannik now to try and complete the job.

Zverev takes his frustrations out on the ball as he pummels a brilliant crosscourt forehand and then does it again to threaten at 0-30 after forcing Sinner into a backhand error into the net.

The Italian retorts with clutch serving and then digs out a magnificent backhand counter punch down the line when he looked dead and buried in the rally.

The second seed falters with a shaky forehand into the net cord and coughs up break back point, but again he produces his best under pressure with an unreturnable delivery.

The defending champion is made to hang about at deuce briefly but two more rocket serves see him consolidate via the scenic route.

Zverev is getting more and more distracted, searching for reasons as to why it hasn’t gone his way so far.

There’s a delay after the German slips a tepid backhand into the net over an issue with the advertising board behind Sinner.

When play resumes Sascha regains his focus with a smash and big serve, but Jannik presses to Pulp (30-30) when he pounces on a volley and rifles the winner down the line.

The world number three then drills a forehand long and it proves very costly as Sinner converts the break point with a stunning crosscourt drop shot.

Zverev zaps away a lovely cross court forehand winner at 30-0 down and gains some traction in the game.

Sinner blasts a make-able forehand into the net from a neutral position and then gets burnt by his insistence on using the dropper again as Sascha blocks a volley away to earn break point.

Sinner responds with a clutch serve and darkens his opponent’s mood further as he digs his way out of trouble with a plus-one forehand and a big serve down the T.

Zverev falters from 15-0 as he slips a weak forehand into the net before he prods a pick-up off a not-so-hot dropper just long.

Sinner presses but drags a backhand just wide and Sascha finally lands a stonking first serve and follows it with an ace to achieve parity on the board.

Sinner stretches out his left leg after reaching to drill a forehand into the net.

The Italian is then caught out as his drop shot is tracked down by Zverev, who blocks away the resulting pass on the volley.

The German comes up with a deep, probing return to force another rushed error long and all of a sudden the second seed has to face up to three break points.

Sinner responds with a pair of clutch serves and claws his way to deuce with a brutal one-two forehand punch.

The four-time major winner continues his run of points with an angled crosscourt volley and ducks out of danger with a wide ace; heartbreaking for Zverev but a moment of pure delight for the Turin faithful.

Zverev pings away a wonderful backhand down the line as the pick of his points before polishing off a game to 15 with a smash off another whopping first serve.

It’s all coming up Sinner at the moment as a dead net cord off his probing backhand leaves Zverev frustrated.

The Italian lands another ace for a 40-0 lead, but Sascha responds with a rasping crosscourt backhand and then gets a glimmer of hope when Jannik drags one of his own off the island.

The second seed snuffs it out immediately with a wide ace and kicks off Set 2 on the front foot.

The Turin crowd’s interest is piqued when Zverev flashes a pair of forehands just wide to fall 0-30 behind.

The German comes up clutch with a venomous serve down the T but shanks a horrible forehand off the island to cough up two set points.

Sinner probes on the first of them but drills just long and Sascha reaches the sanctuary of deuce when he does enough with the plus-one forehand to snare the error.

The world number three hammers down another massive serve to seize the initiative but dribbles a tricky half volley into the net to prolong the examination.

Sinner comes again with a rocket forehand down the line that allows him to conjure up a third set point via a smash and this time he converts as he volleys away in delight off a similar bullet forehand.

Sinner produces great defence to block back Zverev’s piledriver of a backhand down the line and earns his luck as the German jabs a forehand long from the forecourt.

The Italian quickly switches to attack mode as he darts to his left to swish away a crosscourt forehand winner.

Sascha risks too much with a tricky backhand approach down the line that hits the net and Jannik seals the love hold with a delightful dropper.

Zverev continues to land that powerhouse first serve and it makes life all too easy en route to a clean hold.

Sinner lands his sixth ace of the night and jumps all over a short slice to crush an inside-out forehand winner.

The second seed makes a mess of a volley at the net but quickly remedies the situation with a crispo 1-2 punch off the forehand.

Zverev forces the error long off as sharp serve but then gets too passive, bunting a forehand into the net and then being undone by a backhand down the line that allows Sinner sweep forward and slap away a volley.

The Italian defends well in the next exchange but lashes long just as he got back to a neutral position on his baseline.

Zverev takes another step away from danger with a clutch serve and then thunders down a wide ace to tie the set once more.

Sinner kicks off his latest service game with a devilish drop shot that completely flummoxes his opponent.

The second seed follows it with a crisp crosscourt forehand from deep and then forces Sascha to blink first in a crosscourt backhand-to-backhand exchange.

There’s a slight blot on his copybook as he flashes long once more, but a probing serve finishes the job as he pockets another hold for the loss of one point.

There’s a gasp of disappointment from the Turin crowd as Sinner shanks a forehand high into the sky.

It sums up that all has not quite been right with the Italian’s usually rock-solid baseline game.

Zverev takes full advantage as a plus-one forehand does enough damage to ease him level with a game to 15.

Sinner opens with another loose backhand but clicks into gear on serve, nailing a hefty first delivery down the T and then adding a fifth ace to his tally.

The Italian saves the best until last with a rasping crosscourt backhand that Zverev has no real chance of getting back.

It’s far more routine for Sascha as he glides through a hold to 15 to quickly put the disappointment of missing out on a flying start behind him.

It’s an excellent start from Sascha.

Sinner lands an ace down the T to level from 15-30 but then needs a replica after the German had earned break point with a trademark backhand down the line.

Jannik flashes down a third ace of the game from deuce but still has work to do as he bunts a tame backhand low into the net.

A fourth ace fights off a second break point before a plus-one forehand up the line and a clutch wide serve conclude a tricky eight-minute opener.