Tuesday's 1-0 loss left France in second place in qualifying Group I with 10 points from five games, one point behind world and European champions Spain with three games left.
Coach Didier Deschamps blamed the reverse on France's lack of efficiency in a pulsating clash where his side had more chances than their visitors.
Misfiring striker Karim Benzema reached 1,000 minutes without scoring for France, having netted his last goal in 12 appearances in a 4-0 win over Estonia last June.
In sharp contrast, Spain relied on Pedro, who scored the 58th-minute winner at the Stade de France and has now found the net 10 times in his last six starts.
Real Madrid striker Benzema was booed off the pitch when substituted in the 82nd minute after yet another dismal performance.
"I will not say that I don't care. But if there are people whose only occupation is booing, it is their problem," a defiant Benzema told reporters.
"There are periods like this. This one is long but I will continue to work to score. I hope it will come soon."
Team-mate Mathieu Valbuena thought the reception Benzema got was unfair.
"It is harsh because he moved a lot in the first half, after the interval, too. He was very motivated," he said.
Yet, Benzema has not scored in his last 50 attempts, a performance that falls short of what is expected of a world-class striker.
SCORING TOUCH
France's backbone, however, would be complete if Benzema could rediscover his scoring touch.
With the 19-year-old Raphael Varane, who showed great composure in his first two caps, Mamadou Sakho and Laurent Koscielny, Deschamps has three decent centre backs to choose from.
He is also spoilt for choice in the midfield, especially after Juventus' Paul Pogba proved to be impressive against Georgia and Spain.
Franck Ribery and Valbuena are lethal on the flanks with Jeremy Menez a good substitute, but Deschamps is desperate for a finisher, which may explain his determination to stick with Benzema in the hope he comes good.
Olivier Giroud could be an option as an alternative but the Arsenal forward lacks speed and is best used in a 4-4-2 formation, which Deschamps does not favour against teams like Spain.
Loic Remy and Bafetimbi Gomis can be decent substitutes but they also lack the killer instinct Deschamps is looking for.
France next face Georgia away in September.
"Let's take nine points [from the remaining games] and we will see what happens," right back Christophe Jallet said.
Spain, who have dropped four points at home against France and Finland last Friday, travel to Finland in September.
France can just about afford to play without a finisher until the qualifying campaign is over as the play-off spot is virtually in their hands, but they will need to find a solution should they reach the World Cup finals in Brazil.
