F1 Bahrain GP: Alonso concerned by Button's McLaren-Honda failures

Button was struck with his third car failure of the Sakhir weekend in qualifying, after suffering problems in both Friday practice sessions.

Despite an encouraging step forward in pace, with the team getting through to Q2 for the first time this year, Alonso made it clear that what has happened to Button is a worry.

"Definitely this is a concern at the moment," said Alonso. "Reliability is not good enough and we know we need to improve.

"The main priority is to finish the race with both cars - because the more laps we do, the more things we learn.

"We need to go very deep in the investigation of Jenson's car because there have been too many problems this weekend and it is not good.

"It is the way it is. We are not happy with the situation but we are facing reliability problems and performance problems - there are too many things.

"We need to learn to walk before we run and we are in that phase now."

Although mindful of the reliability problems, Alonso did admit that getting out of Q1 for the first time this season was vital for McLaren to prove that progress was being made.

"It is important," he said after ending up 14th.

"It is not a dream come true going into Q2, especially for us because we have higher expectations than going to Q2.

"We knew we were going in the right direction with car performance, but to always go out in Q1 makes some doubts.

"So for the team motivation, for the engineers and mechanics - they were yesterday working until 5am on the car - to have confirmation we are going in the right direction was important and we needed it."

Although Button was disappointed not to get a lap in qualifying, he was remained positive about the improvement in pace.

"We have had less problems than another engine manufacturer has had, and they have been in it for a year already," he said in reference to Renault. "It is just everything has come at once.

"The important thing is we are improving.

"Fernando got through to Q2 which is a good step, but it is a pity I couldn't be there as well.

"There are improvements and we have to stay focused, but it is frustrating when you cannot do a lap in qualifying."