Lewis Hamilton celebrates after winning the Spanish Grand Prix at the Catalunya circuit. File photo: Emilio Morenatti / AP

Barcelona, Spain -  Winning Sunday's Spanish Grand Prix may have been a turning point for Lewis Hamilton and his Mercedes Formula One team, but the champion isn't counting on it.

The next race in Monaco could bring it straight back down to earth, a situation that team boss Toto Wolff said left him feeling "bloody worried".

"I would be careful with predictions," Wolff told reporters on Sunday night as championship leader Hamilton celebrated his second consecutive win and third in Spain. "We have seen performance that swings from racetrack-to-racetrack, and even from day-to-day, and this is how we take it at the moment."

Ferrari, with Sebastian Vettel leading the way, enjoyed a one-two in Monaco in 2017 and, while the Italians may not be feeling quite so confident after the last three races, should go well there again.

Wolff, however, said: "Why our car doesn’t like to be quick around the corners in Monaco, we haven’t found out yet - but we know what went wrong last year.

He pointed out that Catalunya had always been a strong track for Mercedes in races and testing.

"As much as I am overwhelmed by the victory, my mind is already in Monaco and I remember Sunday night wasn’t as pleasant last year."

Solid points

Hamilton qualified only 14th and finished seventh in Monaco in 2017. Now 17 points clear of Vettel after five races, he has some margin of comfort and pointed out that even in races where he has not had a great afternoon this season he has still managed to bank solid points. His situation is also a lot more comfortable than Vettel's, who has now been off the podium for three consecutive races.

"I think this has been a good race in terms of feeling again what I felt in the first race. It shows that it wasn’t just a one-off," said Hamilton, who was on pole at the opener in Australia in March but then lost some confidence in the car.

"But there are a lot of challenging races that we have coming up, Monaco is going to be a serious challenge," he added, highlighting the speed of Australian Daniel Ricciardo in Barcelona.

Ricciardo - on pole for the first time in Monaco in 2016 - set the fastest race lap on Sunday and, perhaps more significantly, was quickest in the last high-downforce sector.

"These different things that are coming up are going to be challenging," Hamilton said. "I don’t think it’s going to be as clear as it was today."