Lewis Hamilton is anticipating another tight contest with Sebastian Vettel when the championship rivals lock horns at the Bahrain Grand Prix.
Hamilton, who is level on points with Vettel at the summit of the title race, appears to be at a slight disadvantage to the Ferrari driver who topped both practice sessions here on Friday.
Indeed Hamilton was only a surprise fifth fastest, but a scrappy lap and then heavy traffic on his next run, suggests Britain's triple world champion has time in his pocket ahead of qualifying later today.
"It was very close, with Ferrari fastest and in race trim they seem a couple of tenths quicker, so I'm expecting a great battle in qualifying and then again on Sunday," said Hamilton ahead of the third round of the championship. "We'll work as hard as we can to try to close that gap."
Although Vettel led the way it was not a day without trouble for him, or his resurgent Ferrari team.
Kimi Raikkonen suffered an engine problem in opening practice - after he stopped on track with smoke billowing from his engine - before Vettel limped back to the pits in the day's second session where his Ferrari mechanics wheeled him 100 yards back to the garage.
"I can't explain why the car stopped altogether, but we were able to recover, restart the engine in the garage and, fortunately, it happened at the end of the lap," Vettel added.
"It was not our best day for us and we still need to do better. The car feels good on a single lap though, and as for race simulation, we can further improve for qualifying."
Jenson Button, meanwhile, has been confirmed as the replacement for Fernando Alonso at next month's Monaco Grand Prix.
The 2009 world champion, who is employed by McLaren as an ambassador, will deputise for Alonso as he heads across the Atlantic to take part in the Indianapolis 500.
"I'm thrilled to be making a one-off return to Formula One, and I couldn't think of a better place to make that return than my adopted home grand prix of Monaco," Button, 37, said.
''I'm supremely fit, having done a lot of triathlon training recently, so I have no worries on that score. And it'll be nice to say 'hi' to all my old Formula One mates, too, and hopefully to give the fans something to cheer about.''