Fernando Alonso's preparations for the new Formula One season were dealt a blow on Thursday after he failed to complete any meaningful running.
A coolant leak on Alonso's McLaren meant the Spaniard missed out on an entire day of testing at the Circuit de Catalunya.
And with Formula One's pre-season schedule restricted to just two tests this year, Alonso will now have only two further days in the MP4-31 before the season starts next month.
"Today was disappointing after starting the first couple of days of the test so positively," said Alonso, who earlier this week committed his future to the British team.
"Still, it's good news that although the issue we had on the car meant we had to miss a lot of today's running, it's not a major problem and will be fixed in time for next week's test.
"Overall, we've managed a good number of laps during this test, which means we have a lot of data to analyse and learn from.
"Over the weekend we'll work hard to get everything prepared for next week, with the aim of getting as much time on track as possible."
While Alonso attempted to put a positive spin on McLaren's troubles, their curtailed running on the fourth and final day will come as a major disappointment to the British team. Indeed, his team-mate Jenson Button was restricted to just 51 laps on Wednesday after a hydraulic leak.
McLaren are bidding to bounce back from the worst season in their coveted history after they managed a paltry 27 points last term.
Next week's final four-day test gets under way here on Tuesday before Melbourne's Albert Park plays host to the season-opening Australian Grand Prix on March 20.