Barcelona twice led through Ousmane Demeble and Paco Alcacer but Iago Aspas earned Celta Vigo a deserved 2-2 draw against Ernesto Valverde's much-changed side after Sergi Roberto was sent off.
Casting an eye towards Saturday's Copa del Rey showdown against Sevilla, Valverde named an experimental line-up and started with a host of regulars, including Lionel Messi and Luis Suarez on the bench.
Somewhat expectedly, Barca lacked their usual fluency in attack and a disorganised defensive showing coughed up glorious chances to Suarez's countryman Maxi Gomez and Brais Mendez before Ousmane Dembele dispatched his maiden LaLiga goal for the visitors in the 36th minute.
Jonny Otta brought Balaidos to its feet with an equaliser in first-half stoppage time and Celta were in the ascendancy until Messi entered the fray to instantly lift the Barcelona performance.
He had no direct involvement in Alcacer's scrambled 64th-minute goal that was not enough to increase Barca's lead at the summit 14 points.
Roberto deservedly being sent off for a crude foul on the relentless Aspas did not help matters and Celta's star man was gifted his 20th goal of the season by an error from the otherwise impressive Marc-Andre ter Stegen eight minute from time – the officials deciding not to punish the final touch coming off his arm.
82' ¡GOOOOOOOL DEEEEEL CELTAAAAAAA! ¡VAMOOOOOOOS! ¡IAGOOOOOOOOO ASPAAAAAAAS! ¡GENIOOOOOOOOOO!2-2 April 17, 2018