World Champion Lewis Hamilton has praised McLaren's progress since the start of the season, but the Briton admits there is still a long way to go for the team.
McLaren has been playing catch-up since it became clear its car was lacking speed during pre-season testing. The team has taken a step forward since the Australian Grand Prix, with Hamilton enjoying his strongest outing in the last race in Bahrain, where he finished in fourth.
Hamilton says the team's progress has been "phenomenal," but reckons there is still work to do before it can fight on top.
"When we tested here we felt we would not be too bad, but when we tested we were 2.5-3 seconds behind the leading car so that was a big shock to the system," said Hamilton in Barcelona on Thursday. "The team has pushed an incredible amount from then on and the progress the team has seen since the first and second days we did here has been phenomenal.
"Fourth in the last race was the result of that, but there is still a long way to go – and we are coming from a long way behind."
The McLaren driver believes the start of the European season this weekend will be good to judge if his team has made real progress compared to its rivals.
"This weekend is a good indication of whether that is the case or not," he said. We have a couple of things on the car, but we don't have a lot going on that are radical steps for us."
Hamilton added that he was impressed McLaren has not been hampered by all the controversies surrounding the team over the past weeks.
"I think what's been impressive is the team have not been effected by it. We've been pushing since the test we had here and through past experiences they have been strong together, and we've focused on the primary goal, for sure the team and the guys back at factory can focus more on getting the car back to the front and that can only be good."