McLaren racing director Eric Boullier has calmed fears over the team's early performances in testing ahead of the new Formula One season.
During Tuesday's session in Barcelona, Stoffel Vandoorne completed just 38 laps amid a trio of mechanical failures and the picture was not much brighter 24 hours later.
Fernando Alonso suffered additional problems, although he did complete 57 circuits, before stopping two hours in due to what was identified as an oil leak.
Having struggled badly with Honda engines, accruing just 30 constructors' points last season, McLaren have switched to Renault for 2018.
Alonso did get back out for the final few minutes of testing on Wednesday and Boullier believes McLaren's early teething problems are to be expected.
"It's just testing," he said. "On the tyres, if you look at the lap time, Red Bull did a test this morning, [they] put on new mediums [and then] new softs.
"They are half a second faster only, so there is not much difference because of the tarmac specification and the temperature as well. We have a technical reason why we want to work on the car with these [hypersoft] tyres.
"[Regarding] the car breaking down, it's testing so we have some little issues which we have to fix, but it's just testing. It's part of the process. We are on top of this.
"It's a new partnership with Renault, completely new packaging for the car as well. This is testing. Give us time and it's fine."
Meanwhile, Red Bull and Mercedes continued to impress - Daniel Ricciardo setting an unofficial track record on hypersoft tyres, 0.353 seconds faster than defending champion Lewis Hamilton, who was running on ultrasofts.