Barcelona were held to a draw 1-1 draw at Roma as they got their Champions League defence under way on Wednesday night.
Luis Suarez gave Barca a 21st-minute lead in the Group E contest but Roma equalised 10 minutes later with a wonder goal from defender Alessandro Florenzi.
Florenzi drilled a right-footed shot from just over the halfway line and the ball cannoned into the back of the net off a post.
Elsewhere in the pool, Hakan Calhanoglu scored a brace either side of Javier Hernandez's first goal for Bayer Leverkusen as the German side saw off BATE Borisov 4-1 at home.
Leverkusen took the lead in the fourth minute through a delightful Admir Mehmedi effort, only for their Belarusian opponents to draw level nine minutes later via Nemanja Milunovic's deflected header.
The hosts went back in front two minutes into the second half when Calhanoglu's shot diverted in off Dzyanis Palyakow.
Hernandez, signed last month from Manchester United, then marked his first Leverkusen start with a tidy right-footed finish in the 59th minute, before Calhanoglu converted a 75th-minute penalty.
Thomas Muller's scoring hot-streak continued as he netted a brace to steer Bayern Munich to a 3-0 win at Olympiakos.
Muller put the Bayern ahead in the 52nd minute with a lofted effort from outside the box which looked as if it had been intended as a cross.
Substitute Mario Gotze then lashed in with a minute of normal time remaining, before Muller converted a penalty in stoppage time to take his tally for the season to eight Bayern goals and 11 overall, including those scored for Germany.
Vitaliy Buyalskyi came off the bench to score a late equaliser and earn Dynamo Kiev a 2-2 draw with Porto in their opening Group C match.
After a two-year absence from the group stages, Kiev made a great start when Oleg Gusev scored after 20 minutes.
Porto were level three minutes later when Vincent Aboubakar outjumped his marker and he put the visitors in front after the break following a corner.
Buyalskyi saved Kiev though, racing onto Serhiy Rybalka's mis-hit drive and firing past Iker Casillas.
Competition newcomers Gent overcame the disadvantage of having two players sent off to come from behind to draw 1-1 at home with Lyon in their Group H encounter.
Gent finished with nine men but goalkeeper Matz Sels made a one-handed penalty save just two minutes from time to ensure a share of the spoils in a drama-filled tie at the Artevelde Stadium.
In the other game in the group, there was drama aplenty as Valencia lost 3-2 to Zenit St Petersburg at the Mestalla.
Hulk opened the scoring in the ninth minute when he sped clear on the left and cracked a shot across goalkeeper Jaume Domenech into the far corner.
His second shortly before half time was even better as he picked up the ball outside the penalty area and smashed it high into the net.
Valencia fullback Joao Cancelo, who hit the post in the second minute, pulled a goal back for the home side 10 minutes into the second half and forward Andre Gomes levelled 17 minutes from time when he netted from a tight angle.
Zenit's Belgium midfielder Axel Witsel grabbed what proved to be the winning goal for the visitors three minutes later with a powerful low strike.