SOCHI, Russia (AP) Nico Rosberg cruised to victory in the Russian Grand Prix on Sunday as his title rival and teammate Lewis Hamilton dodged crashes and battled through the pack for second.
Rosberg has won all four of this season's races - seven in a row including victories from last season - and has a hefty 43-point lead over Hamilton in the title race.
''It's been an awesome weekend, the car has been fantastic. Very, very happy, thanks to everybody,'' Rosberg said, but played down his championship lead.
''Lewis is going to come back of course. He's on it and as motivated as ever. So, early days.''
Pole position and the unbeatable pace of the Mercedes meant Rosberg faced little competition as he won by 25 seconds from Hamilton, who had to fight through the field after starting 10th due to a technical failure in qualifying.
Already up to fifth after an incident-packed first lap in which Ferrari's Sebastian Vettel crashed out, Hamilton passed both Williams cars and the other Ferrari of Kimi Raikkonen to take and hold second.
Hamilton had been closing in on Rosberg in the second half of the race, but backed off after the team warned him of a water-pressure problem. Whether he could have caught Rosberg was doubtful - the German demonstrated he could produce blistering pace when needed with a fast lap just before the end.
''The car felt good. At that time, I was lapping a little quicker than Nico, I was chewing away at (his lead),'' said Hamilton, adding he had no idea how serious the problem with his car was. ''At that point was when I had to back off and I was a second slower.''
Raikkonen was third, 6.9 seconds behind Hamilton. Following another race in which Ferrari was far behind Mercedes, the Finn said the result was ''not exactly what we want, we want to win races.'' Raikkonen is third in the standings, 57 points behind Rosberg.
After the chaotic first lap that featured three retirements, the safety car came out and at the restart on lap 5, Hamilton jumped the Williams of Felipe Massa for fourth and then blasted past Raikkonen's Ferrari three laps later to take third.
Rosberg took full advantage of Mercedes' untouchable pace this weekend in Russia, quickly building a solid lead.
After the race's only round of stops, Hamilton remained stuck behind Valtteri Bottas' Williams, but passed him swiftly. However, he remained 13 seconds behind Rosberg at the halfway point.
Mercedes had flown in a fuel system part by private jet ahead of the race in the rush to repair Hamilton's car following a power unit failure in qualifying. The water pressure problem raised the specter of a repeat failure and ended the battle for the lead.
Rosberg became the first driver other than Hamilton to win in Sochi since the Russian race was added to the calendar in 2014, and received his trophy from President Vladimir Putin.
Fourth went to Bottas, ahead of Massa and Fernando Alonso, who achieved McLaren's best finish of the season with sixth place. Renault's Kevin Magnussen was seventh, with eighth for Romain Grosjean of Haas, followed by Force India's Sergio Perez and the second McLaren of Jenson Button.
Vettel's second non-finish of the season leaves him 67 points behind Rosberg and it will likely be extremely hard for anyone else to challenge Mercedes, whose cars are hugely dominant for the third season in a row.
Vettel, who had already been dropped to seventh on the grid by a penalty, saw his race ended on the first lap after he was knocked into the wall.
Daniil Kvyat of Red Bull, who had also collided with Vettel at the last race in China, struck the Ferrari driver twice on the first lap, the second time punting him into the wall. Vettel vented his anger at the poor driving. ''Honestly, what are we doing here?'' he lamented in an expletive-filled rant over team radio.
Kvyat was given a stop-go penalty that ended his hopes for points and finished a disappointing 15th at his home race, a result unlikely to curb speculation that Red Bull could be eyeing Max Verstappen to take over the Russian's seat.
Kvyat apologized to Vettel. ''I know I made a mistake and I know that I'll learn from that mistake,'' he said.
His teammate Daniel Ricciardo was also damaged in the first-lap chaos and finished 11th.
At the back of the field, Force India's Nico Hulkenberg and Manor's Rio Haryanto both retired on the first lap in a tangle caused by Esteban Gutierrez of Haas.
Verstappen was running strongly in sixth for Toro Rosso but his race ended on lap 35 with an engine failure.