Updated with quotes from Lin Jarvis and Massimo Meregalli.

Yamaha management took the unprecedented step of publicly apologising to factory riders Valentino Rossi and Maverick Vinales after the team's ongoing acceleration problems resulted in their worst qualifying in years, at Austria's Red Bull Ring on Saturday.

Despite Tech3 Yamaha's Johann Zarco claiming sixth, Vinales was left eleventh on the grid and Rossi down in 14th, having failed to even reach Qualifying 2.

The latest setback comes after Yamaha's MotoGP win drought reached 20-races last time in Brno, Yamaha's longest barren run since 1998.

"We, as Yamaha, owe our riders and also you, the media, an explanation," Marketing & Communications manager William Favaro told the assembled media, who had gathered expecting the usual daily debrief with Rossi and Vinales.

Favaro was flanked by Yamaha Racing Managing Director Lin Jarvis, Team Director Massimo Meregalli and Yamaha MotoGP Group Leader & M1 Project Leader Kouji Tsuya, who then took over the microphone.

"Today was a very difficult day for us. We are struggling," Tsuya said, confirming that acceleration performance, related to adjusting the power delivery more precisely, was behind the team's troubles at a track they knew would be "the most difficult" for their present weaknesses.

"I have to apologise to the riders for less acceleration performance today."

Vinales had also suffered sensor problems on his machine in practice (while Rossi had a sprocket failure) all of which prompted Tsuya to conclude:

"We are struggling and have to say sorry to the riders. Now we are working hard as ever to find the solution. After this race we have a [private] test in Misano, before Silverstone. And also after Silverstone, we have a test at Aragon to find a solution.

"But at the moment we will concentrate for tomorrow to get a better result for our riders."