Max Verstappen admitted Red Bull are in for a tough fight in the second half of the season after being overtaken by their improving Formula 1 rivals.

The Dutchman started the season strongly, winning seven of the first 10 races on the calendar, while he and Sergio Perez secured three one-twos in the first four Grands Prix.

However, Red Bull now find themselves under pressure after failing to win any of the last four races, with Verstappen only managing one podium at Silverstone during that run and Perez struggling for form.

Mercedes won three of those four, with Lewis Hamilton winning two and George Russell the other, while McLaren's Oscar Piastri earned his maiden victory in Hungary.

The gap at the top of the constructors' championship is now down to 42 points, thanks to McLaren's 10-race run of consecutive podium finishes.

And now, Verstappen has suggested the Austrian-based team no longer have the fastest car.

"I think they are ahead of us," Verstappen told Sky Sports F1. "It depends. Sometimes McLaren, sometimes Mercedes.

"I think we were faster than Ferrari but coming from P11 [at the Belgian Grand Prix], we didn't have enough time to pass them. We know that we have work to do.

"We know that we want to do better, we are, of course, not satisfied with this, but everyone is doing a great job, and you have to take your hat off for that as well."

Verstappen still holds a 78-point lead over McLaren's Lando Norris in the drivers' championship, the equivalent of three race wins, with the season resuming in the Netherlands at the end of August.