FC Barcelona took a big step towards a seventh successive UEFA Champions League quarter-final appearance as Lionel Messi and Daniel Alves downed ten-man Manchester City FC with a pair of second-half goals.
The pivotal moment of this much-awaited contest arrived eight minutes after the restart when Martín Demichelis upended Messi to concede a penalty, earning himself a red card before the Barcelona forward sent Joe Hart the wrong way from the spot. Barcelona doubled their lead in the final moments through Alves, leaving City with a mountain to climb in the round of 16 second leg on 12 March.
City have earned plaudits for their free-scoring play this season yet took a more cautious approach here. Manager Manuel Pellegrini fielded Aleksandar Kolarov on the left side of midfield and opted for just one striker, Álvaro Negredo spearheading the attack with support from David Silva.
As it was, Negredo was certainly a handful for the visitors' defence in the first period. Although Barcelona dominated possession early on, it was the City forward who had the first chance of note, breaking into the area onto Silva's threaded pass but carrying the ball wide and finding the angle too tight to beat Víctor Valdés.
Alongside the fit-again Fernandinho, Yaya Touré was more preoccupied with his defensive duties than normal and was well placed to stick a foot in when Andrés Iniesta looked poised to pull the trigger on the edge of the home box. When Barcelona did get in a serious attempt on goal, through Xavi Hernández's 25m strike on the half-hour, Hart was equal to it.
At the other end, City sought to profit from the Blaugrana's vulnerability in the air – Valdés got nowhere near one Silva free-kick into the area, leading to a scramble in the Barça goalmouth. Then, on the stroke of half-time, Negredo nodded wide from Jesús Navas's cross to the far post.
After that tight first period, the tie tilted Barcelona's way after 54 minutes after Navas had lost the ball in midfield and Iniesta sent Messi racing clear. Demichelis, caught out of position, brought down his compatriot and Messi made no mistake with his penalty.
A goal and a man up, Barcelona threatened more goals. Xavi blazed over when set up by Alves and then Alves himself burst through on a one-two with Alexis Sánchez but flashed the ball a fraction wide of the far post.
To their credit, City's heads did not drop and Silva forced a low save from Valdés but then came the second goal from the excellent Alves, the Brazilian breaking through on a one-two with substitute Neymar and burying a low shot beyond Hart.