Mercedes and Ferrari renew their rivalry on familiar terrain on Sunday at the Spanish Grand Prix, but it is far too early in the season to make title predictions.
It is said that cars which are fast on the 4.655km Circuit de Catalunya are competitive everywhere else as well.
But the Barcelona race has only been won by the eventual world champion three times in the past decade - Jenson Button in 2009, Sebastian Vettel in 2011 and Lewis Hamilton in 2014.
All teams know the track well, as it is also used for the pre-season tests.
There Ferrari impressed and the first four races confirmed that they have caught up with Mercedes, with Vettel winning twice for the Italian team, and Hamilton and Valtteri Bottas once each for the champions.
“Ferrari is competitive again and is feared by our rivals,” Ferrari president Sergio Marchionne recently told analysts.
Ferrari are just one point behind Mercedes in the constructors’ list while Vettel leads the drivers’ championship with 86 points from Hamilton (73), Bottas (63) and Kimi Raikkonen in the second Ferrari (49).
But the four-time world champion is taking nothing for granted as “we more or less got the maximum” out of the first races.
“Barcelona is another race and there are many races this year,” he said. “We had a very good start. We are here to win, to do our best, but we can still learn and improve.”
Vettel fell just short of hunting down Bottas two weeks ago in Russia as the Finn held on for his first career win, while Hamilton had to settle for fourth with pace problems and will hope to rebound in Spain.
Mercedes motorsport chief Toto Wolff said the team is doing everything to make the car perform well again, and also continues to adapt to no longer being the unchallenged number one in the sport.
“I have the feeling that we are moving in the right direction but we need 24/7 shifts to achieve our ultimate targets,” he said. “This inter-team battle is a totally different situation than what we have seen over the last three years.
"You simply need to adapt to the challenge and that’s what we are doing, playing the hunter as well as being the hunted.
“This fight will continue on to the end of the season and we will be prepared for that battle.”
Wolff added he expects a three-team battle because “Red Bull will also eventually join the club” of title contenders.
Red Bull and their driver Max Verstappen have fond memories of Barcelona as the Dutch teenager scored his first and so far only career win there last year, in his first race for them after joining from sister team Toro Rosso.
“Last year was such a special race to me and in the end we managed to pull it off,” Verstappen said.
“It was an incredible feeling once I passed the finish line, especially in your first race with a new team. Going back to Spain will always mean a lot to me.”
Like the other teams, Red Bull will have made updates to the car and Verstappen said he hopes it will draw them closer to the leaders.
“We have to wait and see what the updates will bring. I hope we can be a bit closer to the top teams,” he said.