The Spaniard was in second until the DRS system on the car's wing jammed open, forcing an unscheduled pitstop that led to an eighth-placed finish at the Bahrain Grand Prix on Sunday.
Despite his bad fortune, Alonso remains upbeat about his chances in his homeland next month.
"We definitely didn't have much luck today and that's a real shame, at the end of what had been such a positive weekend," Alonso told GMA News.
"After the opening laps, when I thought the rear tires had gone off, the pit wall informed me that the DRS was stuck. It wasn't fixed properly at the first stop and so I had to come in for another one.
"From then on, the clear instruction from the pit wall not to use it affected my race. I tried to recover but it was really difficult finding places to overtake without DRS. Having a good race involves a lot of factors, including a bit of luck. Let's hope it balances out very soon, maybe even starting in Barcelona, my home race."
The Spanish Grand Prix takes place on May 12.