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Andre Lotterer in the #2 Audi took the lead from Mark Webber's #20 Porsche with just over two hours remaining of the Le Mans 24 Hours.
The #20 car had led with Timo Bernhard at the wheel but appeared to be carrying some sort of problem as Lotterer closed in. A slow puncture forced Porsche in to an early pit stop which saw Webber take over the car and drop behind the #2 car, but Audi then decided to take track position and kept Lotterer in the car for a fifth stint to be able to pit and remain ahead.
The problems for the #20 Porsche were highlighted when Neel Jani in the sister car cruised past in the final sector and was able to match the Audi pace, but Webber was some five seconds off the pace.
Lucas di Grassi in the #1 Audi is well placed to take advantage of any issues for the Porsche, running quickly although three laps off the lead after a long turbocharger change an hour before.
In LMP2, the #35 Oak Racing Ligier appears to be ailing, with Alex Brundle in the lead but losing eight seconds per lap to the #46 TDS Ligier which is over half a minute behind and has the #38 JOTA car close behind.
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Live text commentary recap of Hour 22: Key moments in bold
11:57 (UK Time)
Lotterer now on his fifth stint in the #2 Audi and he leads Webber in the #20 Porsche by 25s
In comes Lotterer in the #2 Audi. Treluyer waits but Lotterer stays in the car. It's a short stop and the Audi retains the lead
The lead #14 Porsche breezes past the #20 Porsche approaching the Ford Chicane - something definitely not right with the lead car. Jani in the #14 car is able to match the Audis
Lotterer in the 3m26s and absolutely on it at the moment. The #2 Audi might even be able to pit and rejoin still in the lead
Brundle's lead in the LMP2 class is still relatively healthy as he is now just over two minutes ahead of the #46 TDS Ligier which has pitted. Brundle pits now...
Webber four seconds slower on that last lap but the #2 Audi and #20 Porsche out of sync on pit stops for now
The lead LMP2 car is still slow as Brundle registers a 3m48s in the #35 Oak Racing Ligier
Webber hasn't been the quickest driver for Porsche so far in this race and he's going to need to find a little bit extra to keep the Audi from reeling him in after the #2 stops
Lotterer is asked by Audi to tell Treluyer - who is set to take over - how to drive the car. Another stop coming soon...
With the #20 Porsche changing driver it's a longer stop. New tyres for Webber and out he goes
In comes the #20 Porsche and that means Lotterer blasts past in to the lead in the #2 Audi
Could be a problem for the #20 Porsche as the team leap in to action in the garage - Webber running to get ready to jump in for the final stint
Lotterer told by Audi to increase his pace and the #20 Porsche registers a slow 3m35s. The gap now just 33s
The #34 Race Performance Oreca has just been wheeled back in to the garage, currently running seventh in the LMP2 class
Tincknell at the wheel of the #38 JOTA and he's closing in on the second-placed LMP2 car - the #46 TDS Ligier - at around two seconds per lap. The gap 29s now
Bernhard in the lead #20 Porsche is starting to peg the chasing Audi ... and as I say that Lotterer cuts the gap to 45s. The #20 Porsche 5s slower than the #14 Porsche on that lap
Brundle is slow in the LMP2 class-leading #35 Oak Racing Ligier, his lead down to 1m35s now having lost 12s to the #46 TDS Ligier last time round
The #2 Audi takes another two seconds out of the #20 Porshche to cut the gap to 50s. Di Grassi pits the #1 Audi from third
Gaps between leaders in each class: LMP1 = 52s, LMP2 = 1m53s, GTE PRO = 2 laps, GTE AM = 3 laps
Oops. The #58 Ferrari has spun exiting the final corner and is beached in the gravel pointing the wrong way. Yellow flags out at the Ford Chicane as the car is recovered
The gap between the two leaders is 55 seconds. Lotterer will be looking to continue to close that as quickly as possible in the #1 car but must be wary of the problems Audi has been having in this race
In comes Lotterer in the #2 Audi and it's a relatively quick stop. He sets off again in pursuit of the #20 Porsche
Lotterer is closing in on Bernhard on track - three seconds between them - although Lotterer will pit the #2 Audi at the end of this lap
Bernhard pits the #20 Porsche from the lead and rejoins just eight seconds ahead of Lotterer in the #2 Audi