Lewis Hamilton said he will struggle to qualify in the top 10 for the Spanish Grand Prix if Mercedes cannot improve his car after Friday practice.

Mercedes are running the upgrade they introduced in Monaco last week and Hamilton said it was “a difficult day”.

He added: “The long-run pace didn’t look terrible. We just have to work out how to extract more over a single lap.”

Mercedes are one of several teams who entered the weekend at the Circuit de Barcelona-Catalunya interested to find out how a car redesign would affect their competitiveness.

They ran their redesigned car for the first time in Monaco but always said Spain would be the first race where a real judgement of it was possible, and Ferrari and Aston Martin also have significant new parts. Red Bull themselves have a revised floor edge.

Verstappen looked in a league of his own all day, and was 0.170secs quicker than Aston Martin’s Fernando Alonso in second practice.

Nico Hulkenberg’s Haas was third fastest, from Verstappen’s team-mate Sergio Perez, Alpine’s Esteban Ocon and the Ferraris of Charles Leclerc and Carlos Sainz.

George Russell was the lead Mercedes in eighth place, 0.485secs off Verstappen.

Hamilton, who was running his car with a lower-downforce set-up than Russell, said: “Hopefully we will do some changes overnight. It is very close after P5 back to P10. It is impressive to see the improvements everyone seems to have made all around us.

“Ocon, the Alpines are doing great, the Aston Martin second right behind the Red Bull, which is really impressive. It’s not going to be easy, that’s for sure.”

Hamilton said he would welcome the rain that is threatening over the weekend.

“We could do with a helping hand given we are not as quick as we’d like to be,” he said. “There are definitely improvements I know I can make with the set-up, so I will try to get on top of that.”

Sea of green as Spaniards turn out for Alonso

Alonso was cheered by thousands of Spanish fans, many of them wearing the green merchandise of his team.

He said the support reminded him of the mid-2000s when he won his two world titles with Renault before moving to McLaren and engaging in a titanic struggle with Hamilton.

“I heard 67% of the merchandise in the grandstand is green, which is amazing,” Alonso said. “It is going back to the 2005-6-7 years when everything was one colour. I really feel that support and special energy. I feel how enthusiastic they are, so hopefully we will put on a good show.”

Alonso said he was “happy” with the upgrades on the Aston Martin, which centre on new front and rear wings.

“It’s so tight that 0.1-0.2secs could put you in a completely different spot in the classification,” he said, “so don’t pay too much attention to the times [in practice].”

Ferrari have a new sidepod and floor design that moves their car more in the design direction pioneered by Red Bull.

The team hope it will provide the consistency of balance on a long run that has hampered their season so far – after qualifying close to Red Bull, their drivers have struggled with the car in races and tended to fall backwards.

Leclerc said: “It is a great track to test the new upgrades. The feeling is quite OK. We still have a lot of work to do to optimise the new package but it felt pretty good.

“It is closer than ever apart from Red Bull, who are in a league of their own especially in race pace. Everyone else seems to be more or less there.”

Track layout change meets with approval

All the drivers welcomed the changes to the circuit that have been made this year.

The slow and clunky chicane in the final sector has been removed and the lap now ends with two fast right-handers, as it did in the first iteration of the circuit used from 1991 to 2006.

Russell said: “It was fun to drive around the new version of the Barcelona circuit. It’s gone from one of the worst corners in F1 to one of the best corners in F1.”

Sainz said the track was “a lot better, a lot more exciting, has a lot more character and is more demanding with the last two corners the way they are”.