The Blues were made to play a patient game by Danish title-holders Nordsjaelland before eventually overcoming them for a 4-0 win in Copenhagen thanks to a double from Juan Mata, a brilliant free-kick from David Luiz and a late sealer from Ramires to get their campaign off and running.
United survived an early scare when going down a goal at Romanian club CFR Cluj before Robin van Persie saved the day with two clever finishes both from Wayne Rooney passes for a 2-1 victory whilst Celtic produced a late show to beat Spartak Moscow 3-2 in Russia.
Gary Hooper's early opener was cancelled out twofold via Spartak's Emmanuel Emenike before a Dmitriy Kombarov own-goal, after Juan Insaurralde's sending off, and a 90th minute Georgios Samaras header forced a come-from-behind win for the Scottish champions.
Alexis Sanchez and Cesc Fabregas were amongst the goals as Barcelona defeated Benfica 2-0 in Lisbon but it came at a cost for the Catalan giants with captain Carles Puyol coming from the pitch with a suspected broken arm and a late red card to Sergio Busquets.
Tomorrow night sees Manchester City host Borussia Dortmund, Arsenal at home to Olympiakos, Real Madrid away at Ajax, AC Milan at Zenit St Petersburg, Dynamo Kiev up against Dinamo Zagreb, Paris Saint-Germain at FC Porto, Schalke versus Montpellier and Anderlecht at home to Malaga.
2012/13 UEFA Champions League scores