McLaren's Lewis Hamilton accused his future replacement Sergio Perez of 'crazy' driving on Sunday after the two fought for points at the Japanese Grand Prix.
Mexican Perez, who will move from Sauber to replace Hamilton next season when the 2008 Formula One champion joins Mercedes, retired on the 18th of 53 laps after spinning off while trying to pass the Briton at the hairpin.
Perez, who is not a title contender, had successfully made a passing move on Hamilton on lap six before the pit stops reversed the order.
"I thought that he was going to do a crazy manoeuvre, which he did," said Hamilton, who finished fifth, of the first attempt.
"Then (later) when he was behind me I saw it coming again so I moved a little to the inside, thinking that he was going to go up the inside so he couldn't get by, and he just flew down the outside of me. So very interesting..."
Hamilton closed the gap on Ferrari's championship leader Fernando Alonso, who retired at the first corner of the first lap, to 42 points with five races remaining but had few illusions about his title chances.
"I am quite realistic, I know my situation, but the Red Bulls are going to be hard to beat," he declared.
"Everyone should be concerned, they are very quick, they are always very quick in Korea and they (Vettel) have picked up 50 points in the last two races, Fernando should be more worried than I am."
Vettel, winner of the last two championships as well as the last two races, cut Alonso's lead to four points after winning at Suzuka from pole and setting the fastest lap.
The German won on South Korea, the next race on the calendar next weekend, last year and also in India which follows.
McLaren are Red Bull's closest rivals in the constructors' battle, but the champions have score more points in the past two races.