McLaren were left frustrated when red flags, engine failures and electrical problems cut short Jenson Button's running in Bahrain.
The Brit was behind the wheel of the MP4-29 for the final day of pre-season testing but managed just 22 laps due to an assortment of problems.
Button's early running was cut short due to a red flag while an engine failure for his Mercedes power unit cost him valuable time in the afternoon.
Added to that, the MP4-29 also suffered an electrical issue meaning McLaren will head to Melbourne without having had the time to evaluate their new front wing.
"The team's attempts to understand the behavior of its Melbourne-spec front wing which arrived this morning were curtailed by a late morning red flag," the team stated.
"After lunch, Jenson only managed a few laps before suffering a high-mileage internal combustion engine failure, which kept his car in the garage for much
of the afternoon while the unit was replaced.
"At the end of the day, any further attempts to run were hit by an as yet undiagnosed control electronics problem the result of which is that the team had no driver feedback upon which to evaluate the new front wing.
"The engineers will be able to evaluate its strengths using the limited run data we accumulated during the day."
Button finished the final day of testing with the 1:38.111, which was 4.8s off the pace.