McLaren team principal Martin Whitmarsh admitted the return of fuel pump issues made for a frustrating start to the 2013 Formula 1 campaign in testing at Jerez.
Lewis Hamilton retired from the lead of last year's Abu Dhabi Grand Prix with a fuel pump failure. In a bid to rectify the problem McLaren opted for a brand-new design and pump on this year's MP4-28, only for it to fail after just three installation laps.
"Unfortunately, it was a fuel pump failure, the same as we had in Abu Dhabi," Whitmarsh confirmed. "It was frustrating but it's what tests are for.
"The irony is it's a totally new design and a brand-new pump to resolve the problem we had in Abu Dhabi. That's what tests are for. I'd rather it happen here on day one rather than later in the testing sequence or in the race."
After losing the morning's running, Button returned in the afternoon and ended the day 0.8 second faster than the rest of the field. He managed 37 laps in total.