Lionel Messi scored in a ninth consecutive match but his latest double on Saturday was only enough to earn Barcelona a 2-2 draw against Valencia.
Messi instigated another Barca comeback at the Camp Nou before placing an injury doubt over his availability for Wednesday's Copa del Rey Clasico against Real Madrid.
Ernesto Valverde confirmed after the game his captain had felt a "small problem" but insisted it was nothing serious.
"[Messi] has a small problem," Valverde said. "I don't know exactly what he has. We will have to wait to see what medical staff say. If he's in good shape, he'll play on Wednesday [against Madrid]."
Valverde is still unlikely to take any risks given Barcelona's testing month ahead, even if Messi's absence, however brief, would be a blow, particularly while he is in such irresistible form.
Kevin Gameiro and Dani Parejo's penalty gave Valencia a surprise two-goal lead but Messi pulled one back with his own spot-kick before curling in a brilliant equaliser with 26 minutes left.
After their stunning turn-around against Sevilla in midweek, Barca looked destined again to finish the job, but at the end of a breathless contest, Valencia had held on for a point.
"When you don't win, you always feel you have missed something," Valverde said. "But the league is long and there are matches where you come up against a good team. This was one of those."
Messi's 20th and 21st league goals of the season leave his team six points clear of Atletico Madrid, who could cut the gap to three by beating Real Betis on Sunday, with Real Madrid, 11 points back, at home to Alaves.
After eight consecutive Barcelona wins in La Liga, this result perhaps offered the chasing pack a little encouragement at least.
Real could inflict further disruption themselves. The first leg of the Copa del Rey semifinals on Wednesday will be the first of three Clasicos in a month. The latter two will be back-to-back, within four days. But Messi fit and in this sort of form means any confidence Real feel comes with an asterisk.
His 12 goals in his last nine games is the same number the whole Valencia squad managed in their first 15 league matches. Valencia were 15th in December, with only three wins, and their coach Marcelino was under pressure, just six months after propelling them back into the Champions League.