Lewis Hamilton has been reprimanded for reversing in the pit lane after claiming a last-gap pole position for the Bahrain GP.

The stewards looked into a breach of the rules by the world champion after he returned to the pit lane at the end of qualifying. Cars cannot be reversed in an F1 pit lane under their own power.

However, although found guilty of the infringement, Hamilton escaped with a reprimand and his pole position for Sunday's race stands.

'A reprimand has been imposed as no clear instruction was given on where he should park after qualifying,' ruled the stewards.

The Mercedes driver had secured his second successive pole by the slenderest of margins from team-mate Nico Rosberg in the dying stages of Q3.

When is the Bahrain GP on Sky?

Hamilton had been as low as fourth before his final flying lap after an error on his initial flier but produced the fastest lap ever recorded at the Bahrain International Circuit to pip Rosberg by less than a tenth of a second.

"That was a sexy lap!" a jubilant Hamilton shouted as he crossed the line.

Lewis Hamilton says Saturday's qualifying performance meant a lot Lewis Hamilton says Saturday's qualifying performance meant a lot

"Lewis just did a fantastic job," conceded Rosberg. "My lap felt good, I actually thought I was on pole."

Hamilton's pole position is the 51st of his career and was the undisputed highlight of a qualifying hour that otherwise fell flat with only one flying lap set in the final six minutes of Q2.

"It was a relief to finally put a lap together," Hamilton told Sky Sports F1. "On the lap before I was down already to Nico and then l went wide and lost it, so I knew that l had to go out and get everything more on that final lap.

"It means a lot - it felt like my first pole. I nearly lost my voice [on the warm-down lap], it was like scoring a goal!

Rosberg had been the faster Mercedes driver throughout practice and appeared set to claim his seventh pole position in the last eight Saturday outings.

Paul Di Resta takes a look at Lewis Hamilton's Bahrain pole lap. Paul Di Resta takes a look at Lewis Hamilton's Bahrain pole lap.

"It's actually the only lap I've put together all weekend, and it was the last one. I hope that's the first of many," added Hamilton.

"Throughout practice I was going round and it wasn't quite perfect and Nico would be a tenth ahead. So to finally put it together and knowing that l had to improve after going off on my first flying lap, so happy."

Conclusions from Bahrain GP qualifying

Hamilton also divulged that he had set his Mercedes car up with race strategy in mind.

"I think that's maybe why I've been struggling against Nico this weekend," he suggested.

Both Mercedes cars were beaten off the line in Melbourne by Ferrari and Hamilton, who also claimed pole in Australia from Rosberg, has admitted that race starts remain an area of concern for the world champions.

Lewis Hamilton, Nico Rosberg and Sebastian Vettel reflect on qualifying Lewis Hamilton, Nico Rosberg and Sebastian Vettel reflect on qualifying

"It's always important to get a good start. It's something we've been working on, but it's only been a couple of weeks so whether or not we've made big improvements I highly doubt it, but hopefully it is better," he said.

Rosberg, meanwhile, was left to rue his last-gasp defeat by such a narrow margin.

"I was 100 per cent sure l had pole so that was disappointing," the German admitted. "But if there is one track where pole isn't important it is here in Bahrain and so much can happen. It will be an interesting race with a lot of opportunities."