Alonso headed into the final race of the season with an eight-point lead in the Drivers' standings but eventually lost out to Red Bull's Sebastian Vettel.While the German led from the front at the Yas Marina circuit to eventually claim victory and also become F1's youngest ever Champion, Ferrari decided to follow Red Bull's lead in pitting Alonso's nearest challenger, Vettel's team-mate Mark Webber, early.
Webber and Alonso stopped for tyres at the start of laps 12 and 16 respectively but the tactic backfired when both became stuck behind cars that had stopped even earlier behind the safety car.
Alonso and Webber tried and failed to pass Renault's Vitaly Petrov for 40 laps and eventually finished seventh and eighth respectively.
The Spaniard, who needed to finish fourth in the race, ultimately lost the crown to Vettel by just four points.
Costa told Italy's La Repubblica: "We got it wrong. We didn't approach the race to do our best but to obtain an average result that would have been sufficient.
"And when you do that a little thing, a 'Petrov', a safety car, comes along and everything falls apart.
"Never again," he added.
Costa said the mood in the Ferrari garage when they realised their title hopes had gone was bleak.
"When Fernando crossed the line we were all frozen. For five or 10 minutes we stared at the monitor," he said.
"No one budged, no one took off their helmets. No one spoke. No one wanted to accept the reality."
Costa admitted that Ferrari "made impulsive and erroneous decisions" in deciding to pit Alonso early but also criticised the relationship between Red Bull and sister team Toro Rosso.
Both are backed by the Austrian energy drink brand, with Webber easily getting past Toro Rosso driver Jaime Alguersuari after his stop before getting stuck behind Alonso and Petrov.
In conclusion, Costa insisted that responsibilty for Ferrari's failure in Abu Dhabi should not fall on the shoulders of one team member alone.
"Let's be clear, we didn't lose the Championship because of our strategy in Abu Dhabi, but because our car was too slow," he added.
Source: Planet-F1
