A frustrated Lewis Hamilton lost further ground to Nico Rosberg in the championship race after he finished only fifth on Formula One's inaugural visit to Azerbaijan for Sunday's European Grand Prix.
While pole-sitter Rosberg cruised to his fifth victory of the season to extend his lead back to 24 points, Hamilton was left to rue a problem with his Mercedes.
Sebastian Vettel finished second for Ferrari, with Force India's Sergio Perez claiming third after overtaking Kimi Raikkonen on the final lap.
Hamilton was already facing an uphill struggle against the backdrop of Baku’s picturesque city walls and historic buildings after he crashed out of qualifying and started from only 10th.
And the world champion’s charge back through the field was thwarted by an incorrect engine setting which prevented his Mercedes from operating at full power.
Following a clampdown on radio transmissions at the start of the season – introduced in the hope of placing more emphasis on the driver rather than the pit wall – Hamilton’s Mercedes team were forbidden from informing the Briton how to resolve the issue.
“I might not finish this race as I’m going to try and change everything,” said a furious Hamilton as he fiddled with different buttons and knobs on his complex steering wheel. “
"We do not advise that Lewis," was the response from Peter Bonnington, Hamilton's race engineer.
The Briton then asked: “Can I make suggestions and you say if it’s okay or not?”
“No, that’s not allowed”, was the reply. “Let’s just get our heads down and focus on the job.”
With nine laps remaining, Hamilton managed to resolve the issue.
“Thank f***, man, I got power back,” he said, but by then, with an impressive Perez well up the road, it was too late. And Hamilton, winner of the last two grands prix in Monaco and Canada, had to settle for a disappointing fifth.
For Rosberg, he is unlikely to have experienced an easier victory, with his thumping triumph here taking his career tally up to 19 and, more importantly, getting his title charge back on track.
“Yee-hah,” screamed the German over the team radio.
Red Bull's Daniel Ricciardo, who started alongside Rosberg on the front row, could finish only seventh as he desperately struggled with his tyres.
That enabled Vettel to claim the runner-up spot after Raikkonen was instructed by Ferrari to allow his team-mate through. Raikkonen, already due to serve a five-second penalty for illegally crossing the pit-lane entry lane, was then passed by Perez at turn one on the final lap in what was another impressive race for the Mexican.
Elsewhere, Jenson Button finished just outside the points for McLaren after crossing the line in 11th, while his team-mate Fernando Alonso retired in the closing stages. British rookie Jolyon Palmer finished 15th, 12 seconds and one place behind his Renault team-mate Kevin Magnussen.
After the race, Mercedes non-executive chairman Niki Lauda revealed that Rosberg suffered the same technical issue as Hamilton, but was able to resolve it with more ease than his team-mate.
“It is difficult for the drivers,” Lauda said referring to the radio clampdown. “In this case it was a discussion about engine modes, and we can’t tell them. The drivers have to decide themselves. The problem, both cars had, and Nico fixed it quicker than Lewis could.
“I don’t want to blame Lewis for it because it is rather complicated driving and understanding what is going on. The ban is there, so we have to adapt to it.”
Following his win, Rosberg said: “It has been an amazing day. The weekend went perfectly, I am very, very happy.”
Vettel, who also finished second in Montreal one week ago, added: “Obviously today was a great job for us. The pace is there, the car is good and we are coming along. Thanks to the team.”