Force India's Sergio Perez feels a problematic early pit-stop cost him the chance of solid points in the Monaco Grand Prix.
After qualifying ninth for the race, the chance of a points finish for the Mexican looked in his favour after a tough start to his 2018 campaign.
Perez's stop on lap 21 of 78 proved costly after a botched right-rear wheel change allowed many of his rivals to pass him, meaning he was stuck in traffic, struggling to pass the cars in front for the remainder of the race.
With team-mate Esteban Ocon finishing in sixth place, the 28-year old feels it was a lost opportunity to gather more points in Force India's battle with McLaren and Renault for fourth in the Constructors' championship.
"I am disappointed because we didn’t get the result our pace deserved," said Perez.
"We had a problem at the pit stop and this completely ruined our race. Our first stint was strong, we looked after the tyres well and pushed hard just before the stop.
"We had a good rhythm but we pitted slightly early to react to what was happening around us. We lost some time, but in the second part of the race we had good pace.
"Unfortunately, it was impossible to overtake. I was quicker than the cars in front, but you need a big advantage to be able pass around here, especially with these very wide cars.
"I leave Monaco feeling we have lost some important points. Esteban showed what we could do today and it feels like an opportunity lost."
Perez' non-score in Monaco has meant he has dropped to 12th in the Drivers' Championship, after Toro Rosso's Pierre Gasly secured a seventh place to finish to jump the Mexican by one point.