Lewis Hamilton overtakes Nico Rosberg to win in Japan

Mercedes returned to the front of Formula 1 as Lewis Hamilton dominated the Japanese Grand Prix to put a stranglehold on the title race.

Uncompetitive in Singapore last weekend, Mercedes were imperious as Hamilton stroked to victory and Nico Rosberg fought back to finish second.

The German fell back after being forced wide by Hamilton as the team-mates battled in the first two corners.

The manner with which Hamilton took the lead may create tension in the team.

But Rosberg fought back to pass Ferrari's Sebastian Vettel after his second pit stop.

Vettel's team-mate Kimi Raikkonen took fourth, by leapfrogging Williams's Valtteri Bottas in the same phase of the race.

Hamilton's eighth victory in 14 races extends his championship lead to 48 points with 125 still available in the remaining five grands prix.

Decisive start

Hamilton started from second behind Rosberg after making two mistakes on the single qualifying lap. The huge accident suffered by Red Bull's Daniil Kvyat ended the qualifiying session prematurely.

The Briton felt the lap he had to abort for that crash would have put him on pole, and was determined to win somehow.

But he said how he would do so was the "million-dollar question" on a track where overtaking is notoriously difficult and strategy was unlikely to give him a decisive advantage over Rosberg.

So when he made a better start than his team-mate, Hamilton grabbed his chance.

He dived for the inside line through the fast Turn One, and held it as they braked down into Turn Two.

Rosberg, perhaps ill-advisedly, tried to hang on around the outside and Hamilton - inevitably and perfectly legitimately - ran him out of road on the exit.

Rosberg said after the race: "It got really close on the exit of Turn Two and I had to back out of it there and that lost me the race.

"I haven't seen it on TV. For sure it was close - I had to avoid a collision - but it is difficult to comment now."

The loss of momentum dropped Rosberg down to fourth behind Vettel and Bottas as Hamilton streaked off into the distance and, with a string of fastest laps, took control of a race he never looked likely to lose.

The victory was the 41st of his career, putting him level in the all-time list with his childhood hero Ayrton Senna.

Rosberg's fight-back

Rosberg and his Mercedes engineers were left to plot how to pass the two cars in front.

He initially tried to pass Bottas on track, but was told that his engine temperatures were getting dangerously high.

So he dropped back and waited for the first pit stops. Bottas stopped early on lap 11, while Rosberg waited for a further four laps, choosing to use his car's extra pace in the clear air.

The German was still behind the Williams when he returned to the track, but he then dived decisively down the inside into the chicane, leaving the Finn no option but to give way.

Rosberg's next target was to do the same to Vettel. This time, Mercedes used the ploy of stopping first and using the extra grip of fresh tyres to gain the necessary time.

Rosberg, who had fitted the slower 'hard' tyres for his middle stint while Vettel was on the faster 'mediums', pitted on lap 29.

Fitting the mediums for his final stint, he did two quick laps, one of them the fastest of the race to that point.

Vettel, who stopped on the next lap to fit the 'hard' tyres, was defenceless and the Mercedes swept by as the Ferrari returned to the track.

The four-time champion kept the pressure on Rosberg for the rest of the race but was unable to seriously threaten.

It was a crucial boost for Rosberg in their battle for second in the championship, extending the Mercedes driver's advantage over Vettel to 11 points.

"Embarrassing" home race for Honda

Behind Bottas, the remaining points positions were taken by Force India's Nico Hulkenberg in sixth, ahead of the Lotus cars of Romain Grosjean and Pastor Maldonado and the Toro Rosso drivers Max Verstappen and Carlos Sainz.

McLaren's Fernando Alonso finished 11th, fighting valiantly throughout against cars whose engines have considerably more power than his Honda.

But the frustration of being repeatedly passed on the straight as a result of a power deficit of at least 100bhp - and sometimes more than 200bhp, depending on whether the Honda's hybrid boost had run out, its biggest weakness - was too much for the double champion.

"I'm being passed down the straights like a GP2," he said over the radio in reference to the F1 feeder category, after a Sauber had passed him. "This is embarrassing, very embarrassing."

Later, after being overtaken by Verstappen, Alonso said, his frustration boiling over: "GP2 engine, GP2. Rarh."

It will do little to quell speculation that Alonso may not drive for McLaren next season, despite only being in the first year of a three-year contract worth $40m a year.

Japanese GP results

Japanese GP coverage details

Lewis Hamilton has now won twice at Suzuka

Hamilton overtakes Nico Rosberg at the start of the race

Massa's drives into the first corner with damage to his car

Hamilton celebrates after winning his eighth race of the season