Berlin - Holders Barcelona gave away a late equaliser against AC Milan on Tuesday in their opening match of the Champions League group phase.
In Dortmund the German champions Borussia Dortmund were nearly made to rue a number of missed clear-cut chances from the first half as Robin van Persie gave the Premier League side the lead three minutes from the break.
Dortmund equalised with two minutes to go through Serbian midfielder Ivan Perisic, who scored with a brilliant volley.
In the same group, Olympique Marseille won 1-0 at Olympiacos Piraeus, who ended the game with 10 men.
Brazilian striker Pato gave AC Milan an ideal start in Barcelona with an opening minute goal in their Group H match.
However, the holders seemed unphased by their opponents' lead and were rewarded for their enterprising play in the 36th minute when Messi set up Pedro for the equaliser.
David Villa added a second for the home side five minute after the break with a well-taken free-kick. Barcelona then had several more chances to increase their lead, but failed to convert their chances and instead allowed Thiago Silva to equalise in the second minute of injury time with a header.
In the other game in the group Viktoria Plzen managed to secure a 1-1 draw in their first-ever Champions League game against Bate Borisov.
In Group G both matches saw come-back victories, with former champions Porto coming from behind to beat a 10-man Shakhtar Donetsk 2-1, while APOEL Nicosia scored twice in the space of two minutes through Brazilians Gustavo Manduca and Ailton to win 2-1 against Zenit St Petersburg.
The visitors ended the game with 10 players after Bruno Alves was sent off for a second bookable offence in the 76th minute.
German Bundesliga club Bayer Leverkusen slumped to a 2-0 defeat at Chelsea, for whom David Luiz and Juan Manuel Mata scored in the second half.
The other group game saw Genk and Valencia play to a goalless draw in Belgium.
Eight further Champions League matches will be played on Wednesday.
Champions League results on Tuesday:
Group E
At London
Chelsea (ENG) 2 (Luiz 66, Mata 90+2) Bayer Leverkusen (GER) 0
At Genk, Belgium
Genk (BEL) 0 Valencia (ESP) 0
Group F
At Athens
Olympiakos (GRE) 0 Marseille (FRA) 1 (Lucho 50)
At Dortmund, Germany
Borussia Dortmund (GER) 1 (Perisic 88) Arsenal (ENG) 1 (Van Persie 42)
Group G
At Oporto, Portugal
Porto (POR) 2 (Hulk 28, Kleber 51) Shakthar Donetsk (UKR) 1 (Luiz Adriano 12)
At Nicosia
Apoel Nicosia (CYP) 2 (Manduca 73, Ailton 75) Zenit St-Petersburg (RUS) 1 (Zyryanov 63)
Group H
At Barcelona, Spain
Barcelona (ESP) 2 (Pedro 35, Villa 49) AC Milan (ITA) 2 (Pato 1, Silva 90+2)
At Pilsen, Czech Republic
Plzen (CZE) 1 (Bakos 45+1) Bate Borisov (BLR) 1 (Bressan 69)