SPA-FRANCORCHAMPS, Belgium -- Honda's data was showing no signs of a problem when Fernando Alonso reported an engine issue and retired his McLaren from Sunday's Belgian Grand Prix.
Alonso's afternoon got off to a promising start when he moved from 11th to seventh place in the opening corner, but a series of lost positions on the long straight up to Les Combes over the following eight laps relegated him back to his starting position.
"Embarrassing, really embarrassing," Alonso said after being passed by the Haas of Romain Grosjean for tenth position. Not long after he told his engineer "I really don't care too much about the gaps [to rival cars]. This is just a test" before he broke off radio communication altogether.
"Every two or three corners the team was on the radio suggesting different brake bias settings, different differential settings, but as soon as I'd get to the straights the others would even pass me before they opened their DRS," Alonso explained after the race. "So I said to stop radio communication because I had enough work to do inside the cockpit."
After losing more positions and dropping to 12th, Alonso reopened radio communications with his team to ask whether rain was on the way. When the response came back negative, the Spaniard soon reported an engine problem to the pit wall and returned to the garage at the of lap 26 to retire.
Amid suggestions he may have retired on purpose, Honda said after the race that the retirement had been precautionary and not linked to a warning in the data.
"We thought we had the possibility of scoring some points here in Belgium today, so it was disappointing that we finished the race outside of the top ten.
"After starting brilliantly, Fernando then had a tough race overall. He radioed in with what he thought was a problem with the car, and although there was nothing showing in the data, we decided to stop the car as a precaution."
Asked about the issue after the race, Alonso added: "The power loss came all of a sudden, with no warning, but it was already a very difficult race to get into the points. And we know Monza will be similar to this."