Barcelona, Spain (SportsNetwork.com) – The Spanish Grand Prix is the fifth round of the 2015 Formula One world championship, but it begins the European leg for the racing circuit.

Two-time and defending F1 world champion Lewis Hamilton has been atop the point standings since the start of the season. Hamilton has won three races in 2015, including the last two — China (April 12) and Bahrain (April 19). He is also the defending winner of the Spanish GP.

In Friday’s two practice sessions at the Barcelona-Catalunya circuit, Hamilton topped the time charts in practice 2 with a lap in 1 minute, 26.852 seconds, while his Mercedes teammate, Nico Rosberg, was quickest in practice 1 (1:26.828). Hamilton was just 0.07 seconds behind Rosberg in P1.

“It’s been a fairly decent day – mainly working on setup, tweaking the balance bit by bit,” Hamilton said. “It’s often hard to get a good comparison between the sessions with the track and wind conditions changing. The wind was quite strong at times (Friday) and really inconsistent around the lap. The car is quite affected by that, and it was pretty hot out there in the afternoon too. So I think maybe the temperatures also had an effect on lap times.

“The priority was understanding the tires and how they wear because, ultimately, the race is the most important part of the weekend. We’ve not analyzed the times yet, but our pace felt pretty strong.”

In P2, Rosberg was third quickest, while Ferrari’s Sebastian Vettel had the second fastest lap, clocked at 0.408 seconds behind Hamilton.

“I think it’s quite straightforward that the medium (tires) are the faster tires, but today it was a bit slippery for all the cars,” Vettel said. “I think we can improve the car, but the gap with Mercedes is still there. It was not the best lap today, but I believe that in these (hot) conditions, it is difficult for everybody.

“The difference between the two tire compound is quite big on a lap for us, while on the long run, it is a lot smaller, but then when you slide so much, you can’t really extract the performance out of the tires. Today, everyone was sliding a lot, so it’s not entirely fair to judge the new pieces on the car. But most important, there’s nothing wrong with them. They’re working as expected, so we can hopefully build into that.”

While Hamilton has accumulated 93 points this season, Rosberg is 27 points behind. Vettel is only one point in back of Rosberg.

In last year’s Spanish GP, Hamilton and Rosberg staged a thrilling battle, with Hamilton crossing the finish line just 0.6 seconds ahead of Rosberg.

Hamilton started on the pole and only relinquished the lead when he first pitted on lap 22 and then the final time on lap 44. He had an advantage as high as five seconds, but Rosberg cut that margin to less than a second with six laps to go. It was the fourth consecutive victory for Hamilton in the early 2014 season.

Series: Formula One. Date: Sunday, May 10. Race: Spanish Grand Prix. Site: Circuit de Barcelona-Catalunya. Track: 2.892-mile (4.655-kilometer), 16-turn road course. Start Time: 8 a.m. ET. Laps: 66. Miles: 190.825 (307.104 km). 2014 Winner: Lewis Hamilton. Television: NBC Sports Network.