MONZA, Italy (AP) Championship leader Nico Rosberg was fastest in the second practice session for the Italian Grand Prix on Friday, while Mercedes teammate Lewis Hamilton was hindered by car problems.
Hamilton was more than half a second ahead of the pack in the morning session but took part only in the final half hour of the afternoon's 90-minute practice due to an electrical problem.
The Briton completed just 16 laps and was only six hundredths of a second slower than Rosberg, who clocked 1 minute, 26.225 seconds in the course of 41 laps.
''They couldn't start the car, but the guys did a great job to get me back so I got a few laps at least,'' Hamilton said. ''I felt really good after the practice session this morning, and we have definitely got a competitive car this weekend.
''We made some changes over lunch and then another during the session and, although I didn't have a lot of laps, the car feels great. Hopefully, I'll be able to have the full session tomorrow and get some good running. It would be great to have a trouble-free qualifying tomorrow afternoon.''
Hamilton could take satisfaction from posting the quickest time of the day, 1:26.187 on the fastest track on the Formula One circuit. He would not be happy at suffering more car problems after retiring three times this season, as well as enduring a brake failure in qualifying in Germany and a fire in qualifying in Hungary.
Rosberg was 0.808 seconds slower than Hamilton in the morning.
''It seems that we are quick on one lap but on the long run the others were very fast,'' Rosberg said. ''I didn't feel 100 percent confident in the car, so I can't be happy with today, and I have a lot of work to do tonight with the boys.''
Kimi Raikkonen and Fernando Alonso followed in their Ferraris, in front of the Italian team's passionate home fans at La Pista Magica (the magic track).
''Friday in Monza is always a bit different to the others, with a special significance for our team in the weekend of its home race,'' Alonso said. ''The track characteristics also make it one of a kind: Here, you run with low aerodynamic downforce; you feel the car is quicker down the straights and lighter in the corners.
''Towards the end, we were worried we had a problem, but to banish any doubt, we went out for another lap and everything seemed back to normal.''
Hamilton will also be hoping for no more problems as he continues his intense fight for the title with Rosberg. He won at Monza in 2012, while Rosberg has never had a podium finish in Italy.
Rosberg enters with a 29-point lead over Hamilton in the drivers' standings - the biggest it has been all season.
A big part of that gap was built in the controversial Belgian GP two weeks ago, when Rosberg finished second, after crashing into Hamilton early and sending his teammate out of the incident-packed race.
Daniel Ricciardo was third in the standings after winning the last two races in Hungary and Belgium. The Australian was 16th in the morning practice, more than two seconds slower than Hamilton, and improved to 10th in the later practice, 0.7 slower than the Mercedes duo.
His Red Bull teammate Sebastian Vettel was seventh, just behind Valtteri Bottas and Jenson Button, who was second in the morning session.
Kevin Magnussen of McLaren was eighth fastest, followed by Felipe Massa of Williams.
Conditions were dry and cloudy for both sessions, with the sun out at the start of the afternoon.