Fernando Alonso was left "sad" and "disappointed" after spending much of the opening day of Formula One testing in the garage due to issues with his new McLaren.
The two-time world champion was forced off the track after just one installation lap in Barcelona on Monday as his Honda-powered MCL32 encountered an oil systems issue.
Alonso returned after a new power unit was fitted, but only managed 29 laps - less than any other driver at the Circuit de Barcelona-Catalunya.
The 35-year-old, who was 10th quickest out of 11, said: "It's definitely not the perfect start of winter testing.
"In terms of the performance point of view we have to concentrate and try to recover the time. We are disappointed, we are sad to arrive to the first day and not be able to run.
"We are aware of the time we lost, we have four days for each driver before the World Championship starts and now one day is gone.
"So I have three days to prepare a World Championship, so it's not an ideal situation but it's the way it is. There is nothing more we can do from [Monday's test] more than learn from whatever happened to the car and try to recover the time in the next days."
He added: "It's the first day of testing, so you are not too worried or too excited. Even if you are in a very good position or very good position, there is a very long way to go.
"But as I said, [I am] disappointed. You have been working for three months on your physical fitness, on your simulator, on your sponsor commitments, launching the car - I think everyone did an amazing job on this car for many, many months.
"Now you hit the track and go on the installation lap and something breaks down and you lose the day. The time is very important this year with the new regulations, the new tyres."
Lewis Hamilton set the quickest lap of the day for Mercedes.