It marked the latest in a succession of lows for the double world champion who has failed to reach the chequered flag in any of the four grands prix staged so far this season.
The newly-installed American told reporters at the Spanish Grand Prix on Friday that he had watched the previous day s news conference during which two-time champion Alonso, who is taking leave from the team to miss the Monaco Grand Prix later this month and instead race in the Indianapolis 500, issued his personal ultimatum.
Alonso left the circuit after his break down, heading back to his hotel where he played a bit of tennis.
Practice will resume on Saturday before qualifying for Sunday's race.
McLaren's team radio told Alonso to "stop the auto, stop the vehicle, engine problem" as yellowish liquid dripped from the underside.
After suffering an engine failure on the formation lap ahead of the Russian Grand Prix Alonso says Honda's early problems in Barcelona were not a surprise. We see this real power, efficiency, corner speed - things which we were missing in the last couple of years. He finished with the afternoon's slowest time, over three seconds behind pacesetter Lewis Hamilton.
"I didn't want to spend the morning on the sofa watching television. I still hope to be happy in the second half of the year", he added. I believe that on other weekends we have had trouble-free Fridays and Saturdays only to not finish the race on Sunday.
McLaren-Honda boss Zak Brown said he accepted Fernando Alonso s challenge to give him a race winning auto for next year, and had no concerns at him leaving the circuit to play tennis after another engine failure.
If Fernando Alonso's Month of May was meant to generate worldwide interest in the 101st Indianapolis 500, consider the early returns an overwhelming success.The live online coverage of.
"My intention, and my first priority, is to race here (F1) next year, but not just to race..."
Ferrari pair Kimi Raikkonen and Sebastian Vettel were third and fourth, about a second slower than Hamilton.
Even the most casual of race fans likely have noticed all the buzz around Formula One driver Fernando Alonso running in the Indianapolis 500, but unless they're specifically fans of F1, many might think his entry is being over-hyped.
"I don't know what Mercedes was up to".
"Sadness... disappointment... just kind of a state of disbelief", Brown said on his feelings of Alonso's stoppage.