San Francisco Frontiers - Russell says Hamilton has been unlucky  

He added that he did not think he had out-performed team-mate seven-time champion Lewis Hamilton, even if he had outscored him in the opening four races.

"I think the next couple of races are very important for us, as a team," he said ahead of opening practice on Friday. "We have had enough time to gather the data and to develop software and solutions.

"I don't expect us to have a solution this weekend, but we should find a clear direction for the path ahead so Barcelona will be a big event for us."

Russell and Hamilton have struggled with their new car's handling problems, notably the 'porpoising' bouncing sensation it produces on fast straights.

After four races, Hamilton is 13th in the drivers' championship and has written off his hopes of fighting for an eighth title while Russell is fourth.

Russell said he had enjoyed more luck.

"A lot of things have to go your way in racing," he said. "I would say we have been on a par and things have gone for me, my way, but not for him.

"The car has been very challenging to drive...But it looks like it will be hotter here this weekend and we shouldn't be struggling with the tyres."

The champion team are expected to introduce a new rear wing and a beam wing this weekend as well as changes to the front-wing endplates on their car in a bid to improve aerodynamic performance and straight line speed.

Q.Nelson--SFF