Lewis Hamilton’s Mercedes and the McLaren of newly-engaged Jenson Button dominated the third day of Formula One pre-season testing at Bahrain’s Sakhir circuit on Friday as Red Bull struggled again.

Hamilton, who had sat out Thursday’s session, posted a time of 1min 34.263sec on soft tyres in the morning and that remained the day’s benchmark after the second run in the afternoon.

The British 2008 world champion, whose car struggled for reliability after the break for lunch, completed a total of 67 laps.

Hamilton’s strong performance was further proof of Mercedes’ bright showing in testing both here and at Jerez in Spain last month.

Button celebrated his engagement to long-time model girlfriend Jessica Michibata, who was watching from the pits, by registering the second best time of 1:34.976, 0.7sec behind his compatriot, early in his 103-lap run-out.

Mercedes, who supply McLaren’s engine, were also responsible for the third-placed Williams driven by Felipe Massa.

The former Ferrari man was over two seconds adrift of the British duo with a best lap time of 1:37.066.

For world champions Red Bull, who endured a torrid time testing in Jerez last month but appeared in better shape here on Thursday, there was more frustration when they had to suspend testing in the afternoon.

Sebastian Vettel’s new teammate Daniel Ricciardo completed 28 laps but then a mechanical problem to his car’s Renault engine brought a premature end to the day.

His best time of 1:40.781 left him ninth on the time sheets.

The Australian told the BBC’s website: “It was going OK.

“I did some good laps and those came off the back of the more than 50 laps Seb did yesterday, so we’re getting there.

“Obviously, I would have liked to do more this afternoon but we still have tomorrow ahead of us and it’s important to be ready for that. The car is definitely making progress though. It’s coming together bit by bit.”

Red Bull race engineering co-ordinator Andy Damerum revealed to the BBC that this latest issue was unrelated to any of the problems they’d encountered in Spain.

“Because of its nature it means we have to take the car apart,” he said.

“These issues are of course frustrating but this was unrelated to the others so it’s just a case of tackling each issue as it appears. A tough night in prospect but we hope to get a good day in tomorrow.”

The final day of Bahrain testing is on Saturday and the season starts in Melbourne on March 16.