Porsche is hoping to reduce the points gap on Audi in the World Endurance Championship driver standings when the LMP1 heavyweights lock horns at the Circuit of the Americas in Texas this weekend.
Mark Webber, Brendon Hartley and Timo Bernhard moved into second position in the driver standings following their breakthrough win in the 919 Hybrid at the previous Nurburgring race.
The trio are 17 points adrift of the leading Audi combination of Andre Lotterer, Marcel Fassler and Benoit Treluyer.
Porsche, with pole positions at all four races this season and back-to-back race wins at Le Mans and the Nurburgring, tops the manufacturer points on 184, ahead of Audi's 151 with 2014 champions Toyota a distant third on 89.
A new higher downforce aero package run in Germany last month has helped cement the two-litre V4 cylinder 919s as the new powerhouse in LMP1.
While guarded over Porsche's double title prospects, the squad's LMP1 vice-president Fritz Enzinger said the remaining rounds in Texas, Fuji, Shanghai and Bahrain are about fighting for the twin titles.
“Porsche is focusing on the manufacturers' crown, but the drivers' ranking isn't any less exciting,” Enzinger said.
“Our driver crews are 19 and 17 points behind the currently leading trio from Audi (on 95 points), which means they are both within reach of the top.
“In 2014 COTA was the season's most difficult track for us.
“This year we hope to be able to fight for another race win there. But we don't expect to be dominant like we were at the Nürburgring.”
Porsche experienced problems with both 919s at Texas last year when leaders Romain Dumas, Neel Jani and Marc Lieb led before a loss of power in the final hour of the six-hour race saw them eventually finish fourth, one place ahead of the sister car which lost ground during a downpour.
The rapid Kiwi Hartley remains confident after the Nurburgring win but expects the Audi R18 e-tron quattros to bounce back.
“We are very much in the hunt for the World Championship, and our goal is to stand on the top step of the podium in Austin.
“Audi was very strong in Austin last year, so we are expecting a close race.”
Webber said the Circuit of the Americas offers a mix of challenges from long straights to slow corners and elevation changes.
“We had very changeable and challenging weather conditions (in 2014) and learnt a lot in the high temperatures, which is always an extra challenge for the cars and drivers,” Webber said.
Porsche is expecting fuel stops at 30-lap intervals during the six-hour race in green flag running.
Drivers' standings (top three crews)
Andre Lotterer 95
Benoit Treluyer 95
Marcel Fassler 95
Mark Webber 78
Brendon Hartley 78
Timo Bernhard 78
Marc Lieb 76
Neel Jani 76
Romain Dumas 76
Manufacturers' standings
Porsche 184
Audi 151
Toyota 89