Mercedes Formula One driver Lewis Hamilton is making a bid for his fourth Driver’s World Championship. While he has won three times before, he admits that a fourth would mean so much more than the others, thanks in part to a heated rivalry with teammate Nico Rosberg.

“I’ve had ups and downs [in other years] but I think this has definitely been harder because it hasn’t felt so much like fault from me not being focused, or me not training or ­taking the time,” said Hamilton, as he spoke about his season so far. When it comes to outside factors, Formula One fans would be quick to remember two collisions that he’s had with Rosberg this season.

“All race wins feel ­different for a different reason. Sometimes it’s been easier and sometimes it’s been harder, sometimes you’ve felt more stress, sometimes you’ve felt fitter, all these ­different things,” he told The Telegraph.

This season, he started off on a difficult path, immediately trailing behind his teammate. He was 43 points behind at one point, before he managed to jump start his season. He was able to string together six wins within seven races in order to make up the deficit. He now holds a 19-point lead for the return of the season.

The summer break allowed Lewis Hamilton to sit on top of the rankings for a while, but his lead is fragile. The Guardian reports that he is facing a massive grid position penalty due to engine regulations. This means that he could be demoted 10 positions or more at the start the next race. He has already exceeded the allowable number of five engine switches this season, and going down five places could prove crucial.

While it may not be too difficult for him to tick positions off on the track with his Mercedes, his championship position depends largely on where Nico Rosberg finishes. The Belgian Grand Prix takes place on Sunday, Aug. 28.