Lewis Hamilton says competing against Sebastian Vettel in the early stages of the new Formula One season has been more fun than his previous rivalry with Nico Rosberg.
Mercedes' monopoly on both the drivers and constructors' titles in the hybrid era meant that Hamilton's only real rival had been team-mate Rosberg.
Their relationship was at best fraught and frequently boiled over, but is not something Hamilton has to concern himself with following Rosberg's retirement after the German beat him to last year's world title.
Instead Hamilton, now paired with Valtteri Bottas, has come under pressure from four-time world champion Vettel due to the improvements made by Ferrari.
Both Hamilton and Vettel have a race win and a second-place finish to their name after two events this season and, while the Briton concedes competing against a rival from another team is a different challenge, it is one he is enjoying.
Hamilton said: "It is more exciting racing another team, very much like I experienced in 2007 and 2008 [with McLaren].
"Also, growing up seeing races with McLaren and Ferrari, the great teams that were at the top competing with each other was always exciting.
"So to be in amongst the fight with the Silver Arrows and Ferrari, which is also a very historic, great team, I think it's more exciting than just silver at the front.
"When you're racing up against another team there are strengths and weaknesses.
"You know last week [in China] when we were qualifying against the Ferrari they looked like they were going to get pole but we were finding a bit more time on the track, in the blind really, because at the time I was the quickest of the two guys in our garage, so I was having to base myself on myself, I couldn't base myself on Sebastian.
"Definitely having to push the boundaries on your own is more of a challenge, which I love. When you are comparing data and you are constantly pushing each other, it's OK, but it’s not as much fun as competing against an unknown."