Sakhir, Bahrain (SportsNetwork.com) - One week after running the Chinese Grand Prix in Shanghai, Formula One is back on track this weekend with the Bahrain Grand Prix.

This will be the second straight year the Bahrain GP is held at nighttime in the desert.

Based on Friday's two practice sessions, it looks as though Sunday's Bahrain GP will be another thrilling battle between Mercedes and Ferrari. Mercedes dominated the 2014 F1 season, but Ferrari has bounced back in a big way this season and become Mercedes' toughest competitor.

In the first practice for the Bahrain GP, run during the afternoon in hot temperatures, Ferrari driver Kimi Raikkonen topped the time charts with a lap around the Bahrain International Circuit in 1 minute, 37.827 seconds, while his new teammate, Sebastian Vettel, was second quickest, just 0.202 seconds behind Raikkonen. Mercedes drivers Nico Rosberg and Lewis Hamilton placed 15th and 16th, respectively, in that session.

In P2, held during the evening hours in cooler temperatures, Mercedes turned up the heat by leading the way. Rosberg was quickest (1:34.647) and Hamilton second, 0.115 seconds in back of his teammate. Raikkonen placed third, and Vettel was fourth.

"It was a good day today," Rosberg said after the second practice session. "The afternoon session wasn't very useful, as the conditions are so hot and really quite different to what we see in the evening, which is of course when qualifying (Saturday) and the race will be held.

"That makes the second session very valuable. We learned a lot. For example, Ferrari are very good on the long runs. On qualifying laps, we look quicker, but on race pace, they are really strong, so we will have to do a lot of work to find the perfect setup."

With three grand prix completed, Hamilton, the defending F1 world champion, has accumulated the most points with 68, while second-place and four-time world champion Vettel has 55 points. Hamilton won in Australia and China, and Vettel claimed his first victory with Ferrari in Malaysia.

In the constructors' championship standings, Mercedes has 119 points for the season, compared to 79 for Ferrari.

"It's another weekend on another track, with different conditions," Vettel said. "At the moment, we know how strong Mercedes are. They have a very good package, but so do we, and we must make sure that we keep improving it to close the gap. Whatever is going on between the two Mercedes drivers does not affect us. We must look after ourselves. The rest is not in our hands."

The rivalry between Hamilton and Rosberg was renewed last Sunday in China.

After finishing second to Hamilton, Rosberg accused his teammate of deliberately driving too slow and therefore interfering with his pace during the mid-stages of the Chinese GP. Rosberg felt Hamilton's purposeful slow pace backed him up and allowed third-place runner Vettel to gain on him.

Hamilton claimed that he did not drive too slow in an effort to back up Rosberg but managed his pace in order to avoid tire degradation.

"We're moving forwards and we will re-unite as a team this weekend and try to do a great job," Hamilton said on Thursday. "There's no issue between me and Nico. We saw each other (Thursday) morning, and everything is good. They're going to be times when people are unhappy about some things, but we're grown- ups and we move past it."

Last year's night race in Bahrain was a hard-fought between Rosberg and Hamilton. Rosberg started on the pole, but Hamilton grabbed the lead from him on the opening lap.

Hamilton had a sizeable lead over Rosberg before the safety car was deployed on lap 41 for an accident involving Esteban Gutierrez. After the restart with 11 laps to go, the Mercedes drivers swapped the lead multiple times before Hamilton pulled ahead for good. He beat Rosberg to the finish line by just one second.

"Last year, we had an amazing race here," Hamilton said. "It was really fantastic, great fun, a huge, huge challenge for Nico and me. That was the first night race here, and it was honestly the best race, visibly, that I had seen here in Bahrain."

Series: Formula One. Date: Sunday, April 19. Race: Bahrain Grand Prix. Site: Bahrain International Circuit. Track: 3.195-mile (5.412-kilometer), 15-turn road course. Start Time: 11 a.m. ET. Laps: 57. Miles: 182.115 (308.238 km). 2014 Winner: Lewis Hamilton. Television: NBC Sports Network.