Formula One world champion Lewis Hamilton was beaten by Mercedes colleague Nico Rosberg on a dramatic opening day of the 2015 Belgian Grand Prix weekend.

Rosberg topped the timesheets in both Friday’s practice sessions at the Spa-Francorchamps circuit in Belgium, with Hamilton second in each.

The morning session saw Rosberg confined to the garage during early running with an engine problem.

But he recovered to take top spot with a lap of 1m 51.082s, with Silver Arrows colleague Hamilton posting 1m 51.324s for P2.

A rear tyre failure then ruled Rosberg out of the final third of running in the afternoon session.

Rosberg said: “In the second session it was quite a shocking moment for me when my rear tyre failed.

“When you are going as fast as 300km/h and something goes wrong, that’s a horrible feeling.

“I thought I would end up in the wall and, to be honest, it was pure luck that I didn’t.

“We now need to investigate with Pirelli what happened.”

Despite the problem, Nico’s earlier lap time of 1m 49.385s was the fastest of the day, with Hamilton’s best a 1m 49.687s.

Ahead of Saturday’s all-important qualifying session, Hamilton said: “Today [Friday] was generally a good day – no problems with my car, great weather and a lot of fun out on track.

“It’s not often it stays dry here and that makes it even more enjoyable with the way the track flows through great corners like Eau Rouge.

“It was great to be back out there. The car felt good and it felt very natural to be straight back to business which is a positive sign.”

As for his main rivals, Hamilton said: “Nico is very quick so I have some work to do tonight to see where I can find some time.

“Ferrari and Red Bull also look closer here than they have at past weekends, so it’ll be a close run thing and we’ll need to be up for the fight.

“What happened towards the end of P2 with Nico obviously wasn’t good but luckily he’s unhurt and of course the team will be looking into it with Pirelli.

“I have no concerns, though.

“You have to have trust in the car and in the tyres to go out there and push, so it’s not something you think about.”

Both Mercedes cars ran the Prime (medium) tyre in P1, and then the Prime and Option (soft) compound in second practice.

The team will work with Pirelli to determine the cause of Rosberg’s tyre failure this evening

Paddy Lowe, the team’s executive director, said: “Today started reasonably well, with P1 running more or less to plan save a small engine problem for Nico, which the team turned around very quickly.

“We tested a few different items before moving on to a standard P2 programme of Prime and Option runs.

“This ran smoothly until the long run on Options, when a tyre failure for Nico brought out the red flags in the final third of the session.

“With one car ruled out of running, we decided not to continue the regular programme with Lewis until we had understood the problem.

“We’ll be working hard with Pirelli this evening to understand what happened and how we can ensure that we’re operating safely for the rest of the weekend.”

Lowe added: “Overall, though, both drivers were happy with the balance of the car.

“It’s a tough lap to get right, as the ideal downforce levels required vary at different sectors around the track, so our pace was encouraging.

“We will be keeping a close eye on our competitors as always, though.

“Ferrari and Red Bull in particular look strong this weekend, so we’ll need to have good outright pace and the ability to defend at the end of the long straights to come out on top.”