Robert Lewandowski has scored two late goals and Joao Cancelo an 89th-minute winner to lead Barcelona to an extraordinary 3-2 comeback win at home to Celta Vigo.
Rafa Benitez had been eyeing his first big win since returning to coaching in Spain with his visitors ahead 2-0 on Saturday (Sunday AEST) before Lewandowski struck in the 81st minute.
Cancelo then set up Lewandowski to equalise in the 85th before the Portugal right back completed the turnaround.
"It was a great fightback," said the champions' coach Xavi Hernandez, who signed a contract extension through 2025 on Friday.
"It is true we were disorganised at times and didn't make the ball flow like in other games, but the team won in faith and courage."
Barcelona are now tied on points with surprise packets Girona at the top of the table after their fellow Catalans routed Mallorca 5-3.
Real Madrid are one point behind both before they visiting Atletico for the Madrid derby on Sunday.
Jorgen Strand Larsen had put Celta ahead in the 19th minute and substitute Anastasios Douvikas made it 2-0 in the 76th while their five-man defence held Barca in check -- until the final minutes.
Cancelo joined Barcelona on the final day of the transfer window on loan from Manchester City and has made an immediate impact by giving Barcelona a versatile right back.
It was never more evident than when he joined in a last-gasp push against Celta.
After Lewandowski had given Barcelona hope by scooping a shot over goalkeeper Ivan Villar, Cancelo acted as a midfielder to provide an assist for the Poland striker to make it 2-2.
His next move was to make a run through the heart of the defence where he met a lobbed pass by Gavi Paez and guided it home.
Cancelo said he was relieved to have helped his new team after having had what he called a poor performance after turning the ball over several times.
"I made many mistakes, but you just have to keep focused and play until the end," Cancelo said. "We didn't play well and Celta did well defending their area. But it is always better to play poorly and win, than to play well and lose."
It was a bitter loss for Benitez, who took over Celta this summer for his first job in Spain since his short-lived stint with Real Madrid in 2015.
Undefeated Girona are the revelation of the season so far. The modest team from Spain's northeastern Catalonia region, a club partially owned by Manchester City's Abu Dhabi ownership, have won five straight games after drawing their opener.
After beating Granada 4-2 last round, they've now scored nine goals in their last two games.
Mallorca had gone ahead early through a fourth-minute penalty converted by Vedat Muriqi. But Girona roared back with goals by David Lopez, Artem Dovbyk, Ivan Martin, Yangel Herrera and Savio before substitute Abdon Prats reduced the deficit for Mallorca with a late brace.
Australian Associated Press