Mercedes F1 team has let Lewis Hamilton down - Toto Wolff

Hamilton's deficit to F1 title rival Sebastian Vettel has grown from 12 to 20 points in the last two races after Hamilton lost a likely Azerbaijan GP win to a loose headrest and was then hampered by a gearbox-change penalty in Austria.

"My opinion is Lewis has had all the bad luck that you can have," said Wolff.

"We've let him down with the headrest and we've let him down with the gearbox and now it's about time to fight back and hopefully that's going to happen at Silverstone."

Hamilton admitted the gap to Vettel was beginning to get uncomfortable.

"I don't have a crystal ball, but it doesn't look great at the moment," he said.

"And how am I going to turn that [around]? We've still got a long way to go, it could easily switch within one race.

"But the bigger that gap gets, the more pressure builds."

He also defended his clearly frustrated reactions to disappointing races recently.

"It's important for people who are watching, and also people who are reporting, to understand that you have to have patience with us as drivers," said Hamilton.

"You train, you sacrifice everything to make sure that you get the best result possible.

"So when you don't personally deliver, and other things are stacked up against you, it's hard to come out smiling and be, 'Oh, yeah, that's fine,' because that means you don't care enough.

"And the fact is I care more than anything. And there are days where it feels more painful than others, there are other hard days when it's easier to handle and think 'no worries, we'll move forward'."

Wolff said Mercedes was trying to reassure Hamilton after races such as Austria, where fourth was the limit of his progress.

"He wouldn't be as successful as he is if he couldn't feel the pain as much as he does when he has a bad day," said Wolff.

"What I said is that it's 12 points won. It could have been a collision and that would have been a much wider gap to Vettel."

Hamilton's team-mate Valtteri Bottas denied Vettel Red Bull Ring victory and is now within 35 points of the championship lead.

Bottas said he did not "want to shout about it too much" but that going for the 2017 title had "always been the target".

"Since the day I signed with Mercedes what else can you put as a target?" he said.

"It's still early days in the championship, and more than 50% to go, so a massive amount of points to get.

"With this team I'm developing so much every single race, and I feel like I'm getting better every time, even though we've had some unlucky ones as well. But so will the other guys.

"It's still a long year ahead, and I'm sure we'll be in the championship fight."