Mercedes F1's Wolff concedes Rosberg was fortunate with Austin VSC

Red Bull's Daniel Ricciardo was set to finish second to Lewis Hamilton at Austin, only to be undone by the VSC period that followed team-mate Max Verstappen's gearbox failure.

Mercedes brought Hamilton and Rosberg in for their second stops on lap 31, and the reduced speed of Ricciardo - who pitted six laps earlier - meant Rosberg emerged ahead.

Wolff said he accepted the gain, given Mercedes' 2016 startline issues and unreliability including Hamilton's late engine failure at Sepang.

"I think it would be a different scenario [otherwise]," he said.

"We had the pace, and it was very fortunate when the VSC came out.

"We have not been very fortunate in the last few races, so we will take that."

Rosberg acknowledged the VSC played its part in limiting the damage to title rival and race winner Hamilton.

In finishing second, Rosberg lost seven points to Hamilton rather than 10 if he was third, with his championship lead now 26 points with three races remaining.

"It is part of the strategy," Rosberg said of potential safety cars.

"When you go long [in a stint] you know there is a small chance of being able to benefit from those scenarios, as well as being able to give it a run at the end of the race.

"It is part of the game. It came at the right moment for me, for sure."

RED BULLS COULD SHAPE TITLE FIGHT

Red Bull again took the fight to Mercedes over the course of the Austin weekend.

Although Hamilton led a Mercedes one-two in qualifying, Ricciardo passed Rosberg at Turn 2 on the opening lap and held his own until being compromised by the VSC.

Wolff expects Ricciardo and Verstappen to stay in the mix as his drivers fight for the world championship.

"We expected them to be a bit closer in qualifying and the race than it actually was, because on Friday they were very strong," said Wolff.

"They are doing a good job, they have closed up to us, and [engine supplier] Renault is also doing a good job in catching up.

"The rules on the chassis haven't really changed over the last three years, so it's going to be more difficult for us over the last three races."