Ferrari will hope their updated car can prove a match for Mercedes at this weekend's Belgian Grand Prix, as Sebastian Vettel aims to maintain his advantage over Lewis Hamilton in the drivers' standings.
Although Vettel holds a 14-point lead over Hamilton, the latter's team have been the stronger on high-speed circuits - as evidenced by the Briton's victory at Silverstone.
For the first race after Formula One's mid-season break, Ferrari have arrived at Spa-Francorchamps with a car showing several tweaks.
Hamilton - a winner of this race in 2010 and 2015 - topped the timesheets in Friday's rain-hit second practice session with Vettel down in fifth, but Mercedes boss Toto Wolff expects his outfit to face stiff competition when the main action gets under way.
"It's very close. I think it's closer than you can see," Wolff told Sky Sports F1. "Vettel did a fantastic long run, which was much faster than everyone else."
Perhaps unsurprisingly, Vettel also chose to talk up the speed of his rivals.
"They [Mercedes] looked very strong," the four-time world champion was quoted as saying by the BBC. "Whenever they went out, they had the possibility to go fast.
"For me I was not so happy. I did not really find the rhythm, especially on the short run. The long run was better. So overall, I think the car is there to do the job, to go fast, but we just need to get it right on all fronts and I just need to do my job and then we should be fine."
Stoffel Vandoorne - who signed a new contract with McLaren on Wednesday - is guaranteed to start his home race from the back of the grid after multiple elements of his Honda power unit were replaced. The Belgian faces a 35-place grid penalty.
HAMILTON ENDS PRACTICE ON TOP
Another driver to have agreed a contract extension this week, Ferrari's Kimi Raikkonen, was fastest in FP1, which featured a brief red-flag period following a crash for Felipe Massa.
Yet it was Hamilton who set the pace in session two, with a lap 0.262 seconds faster than the Finn's best effort.
"I think we're closer than many other people think," said a nevertheless optimistic Raikkonen. "For sure we can go faster, and then on Saturday afternoon we will see."
Valtteri Bottas in the second Mercedes, Red Bull's Max Verstappen and Vettel rounded out the top five in FP2, the latter's impressive long run suggesting Ferrari can contend strongly this weekend.
Massa played no part in the second session following his accident as Williams changed his chassis. The veteran Brazilian was cleared to race on Thursday by the FIA medical delegate, having withdrawn from the Hungarian Grand Prix due to illness.
1. Sebastian Vettel (Ferrari) - 202 points
2. Lewis Hamilton (Mercedes) - 188 points
3. Valtteri Bottas (Mercedes) - 169 points
4. Daniel Ricciardo (Red Bull) - 117 points
5. Kimi Raikkonen (Ferrari) - 116 points
1. Mercedes - 357 points
2. Ferrari - 318 points
3. Red Bull - 184 points
4. Force India - 101 points
5. Williams - 41 points
2016: Nico Rosberg
2015: Lewis Hamilton
2014: Daniel Ricciardo
Rain arrived during Friday's second practice session, but it appears race day at Spa is likely to be dry.