McLaren endured a troubled start to Formula One’s concluding pre-season test after Stoffel Vandoorne broke down twice inside the opening hour.
Vandoorne had to be pushed back to the garage by his McLaren mechanics at Barcelona’s Circuit de Catalunya when he stopped in the pit lane after completing one lap.
The Belgian returned to the track moments later but then broke down again, this time on the entrance to the pits, and was wheeled back by his McLaren team.
McLaren said an electrical issue was at cause for both failures, and were optimistic Vandoorne would be back in his car before the lunch break.
But the British team will be frustrated at missing the majority of the morning session with only three further days of testing remaining before the new campaign gets under way in Melbourne on March 25.
A faulty wheel nut cost Fernando Alonso valuable track time on the first day at Barcelona last week, while Vandoorne did not complete any running last Tuesday afternoon following mechanical gremlins.
McLaren, who finished last but one in the constructors’ championship last year, expect to be back at the sharp end of the grid in 2018 after ending their nightmare relationship with engine partner Honda and teaming up with Renault.
Mercedes’ Valtteri Bottas led the way from Ferrari driver Sebastian Vettel on the opening morning. Bottas and Vettel were separated by just one tenth of a second with Red Bull’s Max Verstappen third in the order.
Bottas’s Mercedes team-mate Lewis Hamilton is due to take over testing duties in Barcelona on Tuesday afternoon.