Manchester City were held by Napoli and Manchester United drew with Benfica in Lisbon in their opening games of their Champions League campaigns.
Aleksandar Kolarov's late free-kick rescued Manchester City a point on their Champions League debut after an entertaining 1-1 draw with Napoli at the Etihad Stadium.
Both sides had chances throughout the 90 minutes with City hitting the woodwork twice and Napoli also striking the woodwork as well as seeing a shot cleared off the line.
Napoli stunned the home fans with the opener on 69 minutes following a lightening counter attack from the visitors.
Gareth Barry lost the ball in midfield to Christian Maggio who ran unchallenged towards City's goal before slipping in Cavani to slide the ball between Joe Hart's legs.
City drew level 15 minutes when Kolarov's curled a superb free-kick past Napoli keeper Morgan De Sanctis at his near post with the defender's reward for equalising being immediately substituted by Roberto Mancini.
City's next opponents in Group A Bayern Munich signalled their intentions with an impressive 2-0 win over Villarreal at El Madrigal.
Toni Kroos gave Bayern the perfect start with the opener after just seven minutes following some fine approach play from Franck Ribery and Rafinha made the game safe with a second 14 minutes from time.
Ryan Giggs came to Manchester United's rescue against Benfia with a superb goal to secure them a 1-1 draw at the Estadio da Luz.
Benfica broke the deadlock on 24 minutes with a fine strike from Paraguayan ace Oscar Cardozo.
Nicolas Gaitan picked out Cardozo with a superb pass and the striker took the ball down on his chest and past Jonny Evans before smashing his shot past Andrews Lindegaard from 16 yards.
United drew level, somewhat against the run of play, three minutes before the break through the evergreen Giggs.
Giggs cut across the edge of the box and fizzed in a superb shot into the top corner to stun the home fans.
Both sides had chances to win the game in the second half, but they had to content themselves with a point apiece.
In the other game in Group C, Alexander Frei's late penalty earned Basel a 2-1 victory over Romanian newcomers Otelul Galati at St Jakob-Park.
Fabian Frei fired Basle in front on 39 minutes, but Marius Pena hit back for Galati just before the hour mark with a close-range finish.
Galati were reduced to ten men six minutes from time when Adrian Salageanu was sent off for felling Basle captain Maroc Streller inside the box and Alexander Frei slotted home the penalty.
Basel ended the game with ten men of their own with Benjamin Huggel sent off two minutes from time for a second bookable offence.
Nine-time winners Real Madrid made a winning start to their Champions League campaign with a 1-0 win over Dinamo Zagreb in Croatia.
Angel Di Maria scored the only goal of the game on 53 minutes after being teed up by Marcelo.
Marcelo was later sent off for Real for a second bookable offence after diving.
In the other game in Group D Ajax and Lyon played out a goalless draw at the Amsterdam ArenA.
Trabzonspor stunned Inter Milan with a memorable 1-0 win over the Italians at the San Siro.
Ondrej Celustka grabbed the winner for Trabzonspor 14 minutes from time to give the Turkish outfit a famous victory.
In the other game in Group B Seydou Doumbia's last-gasp goal earned CSKA Moscow an unlikely 2-2 draw with Lille in France.
French champions Lille looked like getting off to a winning start after racing into a 2-0 lead, but Doumbia struck twice late on to earn the Russians a point.
Moussa Sow gave the home side the lead right on the stroke of half-time with a clever back-heel after his initial shot came back off the post.
Lille doubled their advantage just before the hour mark when Benoit Pedretti curled the ball home from the edge of the box after a brilliant dummy from Eden Hazard.
Doumbia pulled a goal back for CSKA 18 minutes from time and he grabbed the equaliser in the final minute to stun the home side.