Updated

Barcelona, Spain (SportsNetwork.com) - Barcelona clinched the top spot in Champions League Group H on Wednesday as Neymar scored three times to lead the club to a 6-1 thrashing of Celtic at the Camp Nou.

Barca entered the day two points clear of second-place AC Milan, and the Catalan side got off to a flying start with Gerard Pique scoring from close range after just seven minutes.

Neymar played provider in the 39th minute for a goal from Pedro, and he scored the first of his three goals shortly before the break with a tap in from Martin Montoya's cross.

The Brazilian made it 4-0 in favor of Barca in the 48th when he fired home a left-footed shot from the top of the penalty area after being picked out by Xavi, while his hat trick was complete 10 minutes later after a good setup from Adriano.

Cristian Tello got in on the scoring in the 72nd with Adriano setting up the goal once more, and Georgios Samaras netted a consolation strike a few minutes from time for the visitors.

Milan will join Barca in the knockout round after the Rossoneri held on for a 0-0 home draw with Ajax.

The Dutch side needed a win to overtake Milan, and they had their share of chances after Riccardo Montolivo was sent off in the 22nd minute for the hosts. However, Ajax was unable to produce the one moment of magic that it needed and the club will be headed to the Europa League.

There was plenty of drama in Group F as Borussia Dortmund got an 87th-minute goal from Kevin Grosskreutz to top Marseille, 2-1, while Napoli's 2-0 victory over Arsenal wasn't enough for the Italian side to advance.

Instead Napoli will be headed to the Europa League, while Dortmund wins the group and the Gunners finish second on goal difference.

Chelsea was unconvincing, but the Blues did enough to clinch Group E with a 1-0 home triumph against Steaua Bucharest courtesy of Demba Ba's 10th-minute goal. Schalke secured second place by downing 10-man FC Basel, 2-0, with goals from Julian Draxler and Joel Matip after Ivan Ivanov was sent off in the 31st minute.

Zenit St Petersburg lost 4-1 at Austria Vienna, but the Russian outfit still managed to sneak into the knockout round in second place after Group G winners Atletico Madrid topped FC Porto, 2-0.

Atletico had already locked up first place, while Porto could have advanced as well with a win. But first-half goals from Raul Garcia and Diego Costa were enough as Porto's Josue also failed to convert a penalty kick in the 28th minute.