Lewis Hamilton admitted he "enjoyed the ride" as he won at a wet Suzuka to extend his championship lead, but a serious injury to Jules Bianchi, the Marussia driver, would overshadow the Japanese Grand Prix.

Reports last night suggested that the 25-year-old had undergone an operation on a serious head injury and was breathing on his own.

Rain had long threatened the running of a grand prix which could yet prove pivotal in Hamilton's title battle with his Mercedes team-mate and pole sitter Nico Rosberg. Despite the conditions, the Englishman was able to outpace his nearest rival to finish the shortened race in front.

The field started the race behind the safety car but a red flag stopped the action after just two laps as the heavy rain over Suzuka - a consequence of Typhoon Phanfone - continued to fall. Once the race had restarted there followed a prolonged dry spell during which time Hamilton both caught up with and then passed Rosberg on lap 29 before disappearing into the distance.

The race would not be completed fully, though, as the rain returned and driving conditions deteriorated. The red flags came out again after Bianchi crashed out late on. The Frenchman was seen to aquaplane and left the track in the same place that Sauber's Adrian Sutil suffered a crash on the previous lap. Bianchi was understood to have crashed into the recovery vehicle that was in the process of removing Sutil's car and, an ambulance having been deployed, the race was halted after 44 laps and Hamilton declared the winner.

The victory moves the 2008 champion 10 points ahead of Rosberg with four races remaining but Hamilton, alongside the rest of the drivers, was subdued in the aftermath of Bianchi's incident, which knocked the Marussia driver knocked unconscious.

"It's been an interesting weekend," said Hamilton, who is 10 points ahead of Rosberg. "Our first thoughts go to Jules; it overshadows everything else when one of our colleagues is injured and we are praying for him. Next to this, the race result doesn't seem significant at all.

"Generally the car was absolutely fantastic through the race and once I passed Nico I was able to really manage the gap and enjoy the ride. Obviously it didn't finish the way we would have hoped."

Rosberg, who could not convert an eighth pole position of the season into the win which would have put him top of the drivers' standings, conceded Hamilton had been the superior driver on the day. "All in all, Lewis just did a better job than me and deserves to win," he said.

Sebastian Vettel completed the podium in Japan, with the four-time world champion acknowledging that he will leave Red Bull at the end of the season. He edged out team-mate Daniel Ricciardo, who finished fourth ahead of McLaren's Jenson Button.

As they waited for news on Bianchi, the F1 community was also united in grief last night after former driver Andrea de Cesaris was killed in a motorbike accident in Rome.

The Italian driver raced between 1980 and 1994 and started in 208 races, although he never won a Grand Prix. His teams included McLaren, Jordan and Brabham.