SEOUL, South Korea (AP) - Heading into this weekend's Korean Grand Prix, the Formula One drivers' championship is shaping up as a duel between defending champion Sebastian Vettel of Red Bull and leader Fernando Alonso of Ferrari.
Vettel took his second consecutive checkered flag at the Japanese GP on Sunday to move within four points of Alonso with five races left. Alonso's lead was further eroded after he crashed on the first turn in Suzuka.
Vettel's dominating win from the pole at Suzuka made him the first driver this season to record back-to-back victories, and he joined Alonso and Mercedes-bound Lewis Hamilton as the only drivers to win three times this season.
Despite his recent success, Vettel said a lot of things can change between now and the end of the season.
"Things can change very quickly," said Vettel, who also won last year's Korean GP. "It's much closer now but every weekend can be different. It's a very new calendar for all of us this year with back-to-back races in Japan and Korea and then in America and Brazil, so we just have to focus on each individual race and see what happens."
Ferrari chairman Luca di Montezemolo said Alonso has been a victim of bad luck and, if not for the mistakes of other drivers, would be in a better position.
"We know we can count on the strongest driver around at the moment, and it's only mistakes from others at Spa and again at Suzuka that have prevented him from having a more comfortable lead over his rivals," Montezemolo said.
Alonso was unable to finish the Belgium GP after a spectacular crash caused by Lotus driver Romain Grosjean. The Spaniard also crashed at the Japan race after Lotus driver Kimi Raikonnen made contact with his Ferrari at the first turn.
"Let's not forget that," Montezemolo said. "But for those two collisions, today Fernando would have had at least 30 points more - and that's a conservative estimate."
Hamilton remains optimistic he can assert himself in the title chase after his fifth-place finish in Japan kept the McLaren driver fourth in the standings, 42 points off the lead.
"I think we've had the potential to win both Korean races in the past," Hamilton said. "But I've never had a race weekend there on which everything has gone quite right for me. We've got momentum on our side once again, so I head to Korea determined to fight for victory."
Raikonnen is still in contention in third, 37 points back, despite not having won a race all season.
Mercedes driver Michael Schumacher, who announced last week that he will retire at the end of the season, said he is looking forward to the race in South Korea after finishing 11th in Japan.
"The basic characteristics should be more favorable for us than in Japan," Schumacher said. "So we're heading to Korea in a positive mood."