Audi continues to lead the FIA WEC Six Hours of Bahrain at the half-distance mark, with the pole-sitting No. 8 R18 of Lucas di Grassi out front.
The Brazilian resumed the lead from the sister No. 7 car of Benoit Treluyer in the third round of pitstops, after Oliver Jarvis had earlier allowed Andre Lotterer through.
However, the No. 7 car is currently under investigation for a pit infringement.
The No. 1 Porsche 919 Hybrid is third with Timo Bernhard at the wheel, after seeing off the challenge of the No. 5 Toyota TS050 Hybrid.
Sebastien Buemi had briefly taken the position away following the first round of pitstops, but Mark Webber was able to repass the Toyota when Buemi locked up and ran wide at turn one on lap 43.
Anthony Davidson was 20 seconds behind Bernhard, with Kamui Kobayashi a further eight seconds back in the sister Toyota.
After suffering a puncture in the first hour, the No. 2 Porsche remains a lap off the lead in sixth, but the struggles of the No. 6 Toyota means they remain on course for the title.
In LMP2, Nicolas Lapierre reclaimed the lead for Signatech-Alpine after Bruno Senna had jumped him in the pits.
The No. 43 RGR Ligier JS P2 Nissan began to struggle for tire life towards the end of Senna’s stint, which allowed Lapierre to catch and pass him.
Ryan Dalziel was second at half-distance in the No. 31 Tequila Patron ESM Ligier Nissan after passing Ricardo Gonzalez, although Chris Cumming has yet to drive.
Aston Martin suffered a difficult end to hour three, as Daren Turner lose a wheel on the GTE-Pro class-leading No. 97 Vantage GTE.
Turner had been leading an AMR 1-2, with Nicki Thiim taking second from early leader Gianmaria Bruni at turn one on lap 67.
After a three minute spell in the garage, the No. 97 car re-joined a lap down.
Despite the incident, Aston Martin remain well-placed to win the GT Drivers and GTE-Pro teams titles.
Meanwhile, Porsches sit first and second in GTE-Am, with David Heinemeier Hansson’s No. 88 Abu Dhabi-Proton Racing Porsche 911 RSR leading Christian Ried’s identical KCMG machine.
The lead switched hands in hour two when Patrick Long pressured Mathias Lauda into a spin, which resulted in the Austrian flat-spotting its tires and losing second to Joel Camathias.
The race would go from bad to worse for the Aston Martin, when Paul Dalla Lana pulled off with engine trouble at half-distance.
As a result, the No. 83 AF Corse Ferrari F458 Italia is confirmed as the class champion.