LONDON, England (AP) — Barcelona and Manchester United erased early deficits to stay perfect in the Champions League group stage yesterday, but Chelsea got the first loss of their title defence and jeopardised their qualification hopes.

Jordi Alba's goal four minutes into second-half stoppage time snatched a 2-1 victory for Barcelona over Celtic, keeping the competition favourites top of Group G after three games.

United's comeback was even more impressive, recovering from two goals down to beat Braga, 3-2, at Old Trafford, thanks to two goals by Javier Hernandez.

Chelsea lost 2-1 at Shakhtar Donetsk to fall three points behind the Ukrainian side in Group E. Juventus couldn't capitalise on Chelsea's slip-up, however, surprisingly drawing 1-1 at Denmark FC Nordsjaelland.

After their stunning 3-1 win over Bayern Munich last time out, Belarus side BATE Borisov came back down to earth with a 3-0 home loss to Valencia to cede their lead of Group F to the Spanish team on goal difference.

Bayern, last season's beaten finalists, are also on six points in a tight group after Thomas Mueller's first-half penalty clinched a 1-0 victory at Lille.

Also, Spartak Moscow beat Benfica 2-1 to get off the mark in Barcelona's group and move a point behind Celtic in the battle for second. Cluj conceded a late equaliser to draw 1-1 at Galatasaray but are still second behind Man United in their group.

Barcelona won their 100th Champions League match and set a new club record of 18 home matches in Europe without a loss, but the win over Celtic was much tighter than expected.

Celtic took a surprising 18th-minute lead when Javier Mascherano deflected a free kick into his own net and the Scottish side defended stoutly before Andres Iniesta tied it in the 45th.

Celtic goalkeeper Fraser Forster made a string of brilliant saves but was beaten by Alba deep into injury time, the Spain left back glancing in a cross from Adriano.

United also claimed a third straight win the hard way, after Brazilian forward Alan had taken advantage of some typically shoddy defending from United this season to put Braga 2-0 ahead after 20 minutes.

Hernandez scored either side of a scrappy goal by Jonny Evans to leave United just one win away from qualification. That would make up for its surprise exit at the group stage last season.