Nico Rosberg admits he is pleased that Lewis Hamilton has signed a new contract, but concedes that their rivalry will always be complicated.
The German extended his Mercedes stay last year while Hamilton only penned an extension to his deal in the build-up to the Monaco Grand Prix this weekend.
It means the two will remain team-mates for the next few years, putting their friendship to the test.
"I congratulated Lewis, " Rosberg said. "I am sure it is a very exciting moment to sign a contract. We have a great battle, that is what racing is about.
"There’s the internal [battle], and we have to think about the team, and at the same time we think about beating each other. It’s always going to be complicated, and both of us want to win.
"At the moment it is a neutral relationship, so it is working okay between us and we are really pushing each other. It shouldn't be underestimated how we are pushing each other to higher and higher levels all the time. It is also great for the team, this internal battle. It is good to know now that future is going to be like that."