DS Techeetah driver Vergne opened his account in FP2 first, posting a 1m40.655s on his first timed run – still six tenths shy of Mortara’s 1m40.022s from the opening practice session.
But the Frenchman was then displaced by Oliver Rowland – who had recovered from an FP1 scuffle with Vergne – at the top, with the Mahindra driver indulging in a number of excursions throughout the two sessions.
Lucas di Grassi then picked Rowland off the top spot, shaving eight hundredths off the headline time, but came under attack from Andretti’s Jake Dennis – who went into P2 despite touching the wall on the exit of Turn 12 and was left to complete the lap with slightly damaged rear-left suspension.
Mortara then hit back, stating his intent with a 1m39.580s – and his tenure at the top was extended by a lengthy yellow flag at Turn 7, where Rowland locked up and was left to perform an Austin Powers tribute act as he attempted to turn his car around.
Nyck de Vries then chopped two tenths off Mortara’s time, setting a 1m39.368s to overhaul his fellow Mercedes-powered competitor.
The session was then interrupted with just over 10 minutes remaining; Oliver Askew clipped the inside wall at the Turn 12 chicane and pulled over at the side of the road thereafter, and was immediately followed by Andre Lotterer’s carbon-copy wall contact – causing both damage to their front-right suspension.
Askew limped back to the pits while Lotterer’s Porsche was tucked behind the nearby marshals’ post, allowing the session to resume with eight minutes left.
Dennis shook off his earlier suspension issues to move to the top, pipping de Vries by a hundredth of a second, before Vergne then surged to the top with a 1m39.082s.
Pascal Wehrlein crossed the line just before the chequered flag to move up to second, avenging the fortunes of Porsche team-mate Lotterer, while Sam Bird displaced Dennis from third.
De Vries was fifth over Mitch Evans, while Antonio Felix da Costa was not as comfortable as his team-mate Vergne and was seventh overall – having snatched at the brakes a number of times throughout the session.
Mortara was eighth in FP2 having been unable to repeat his presence at the top of the timesheets, with Stoffel Vandoorne ninth ahead of Robin Frijns – who recovered from a Turn 10 spin to complete the top 10.
Evans had been second behind Mortara in FP1, and showed improved pace for Jaguar after a difficult opening three races.
Evans and team-mate Sam Bird set the early pace in the post-dawn session, before Frijns took the times into the 1m41s bracket.
Vergne then took control of the session with 10 minutes left, but fellow Techeetah driver da Costa wound the times into the 1m40s.
Evans reclaimed top spot from the Portuguese driver by two tenths, but Mortara hammered in a 1m40.022s - half a second to the good at that stage.
Although Evans closed the gap, Mortara’s time proved unassailable by the end – particularly after the contact between Vergne and Rowland fired the latter into the wall at the Turn 12/13 chicane.
Vergne was on a full-power lap and tried to stuff his car down the inside of Rowland's, making it through the corner but shoving the Yorkshireman into the wall – prompting the emergence of the double yellow flags.
Rowland was able to back out of the barrier with only cosmetic damage to the car, but his partial clogging of the circuit left Dennis rooted to the bottom of the timesheets; the Andretti driver’s full-power lap had yielded a fastest middle sector, but his hopes of climbing the order were promptly dashed.
