Di Grassi grabs pole in controversial session

Di Grassi claimed his first pole of the season with a lap of 1m13.948s but is one of three drivers under investigation for clipping a bollard at the Uruguayan coastal circuit's high-speed Turn 14/15 chicane.

Lynn, who finished 0.241 seconds behind the reigning champion, also hit the orange installation and broke his front wing in the process during his flying lap.

Mitch Evans qualified third after striking the wall on the exit of the double left-hander at the end of the circuit's first leg and gave away 0.6s to di Grassi as he damaged his right-front wheel in the incident.

But the Jaguar driver did not touch the bollard at the chicane and stands to benefit if the drivers above him are punished.

Oliver Turvey qualified fourth for NIO, but is also under investigation for the same infraction as di Grassi and Lynn.

Championship leader Jean-Eric Vergne topped the group qualifying session, but abandoned his superpole lap after striking the wall at the first chicane.

Mexico winner Daniel Abt qualified in sixth place after Vergne bumped him from superpole late-on with the fastest time a 1m13.672s during the group running.

Sebastien Buemi, who set the fastest time in FP1 and won FE's first two races in Uruguay in seasons one and two, did not progress from the final group to superpole and will start seventh after losing time in the tail end of his flying lap.

Andre Lotterer finished eighth ahead of Maro Engel - another driver to brush the wall - and Sam Bird, third in the championship coming into the weekend, rounded out the top 10 for Virgin.

Another title contender - Mahindra's Felix Rosenqvist - wound up 14th after clipping the wall at the first chicane and then again exiting Turns 7 and 8.

Three drivers who crashed brought up the rear of the field in 18th, 19th and 20th.

Nick Heidfeld crashed out late during the third group's running as he understeered into the wall at Turn 17, the last chicane just before the final hairpin.

Nelson Piquet flew through the first sector during his flying lap in group four, but the Jaguar driver hit the blue sausage kerb at the Turns 10/11 chicane and then clattered into the wall on the exit as a result.

Nico Prost brought up the rear of the field after crashing at the high-speed Turn 14/15 chicane.

The Renault driver ran over the kerbs on the left-hander entry and later reported that the steering was damaged in the impact, which caused him to jump across the second apex and go straight into the wall on the outside.