Lionel Messi
Messi's penalty gave Barcelona the initiative.

Lionel Messi's ice-cool penalty and Dani Alves' stoppage time second secured Barcelona a healthy first leg advantage in the Champions League last 16 tie against 10-man Manchester City at the Etihad Stadium.

The four-time Ballon d'Or winner was fouled by Martin Demichelis, who was subsequently dismissed, before converting from the spot to hand the four-time European Cup winners the initiative in the second half.

City toiled for much of the evening and rarely threatened Victor Valdes' goal either side of Messi's opener, with Spanish pair Alvaro Negredo and David Silva producing the only meaningful efforts as Manuel Pellegrini's men failed to reproduce their devastating league form.

And Alves rubbed salt in the wound with a late second, which all but ends City's hopes of staging a second leg come back.

After suffering a 15th career defeat to Barcelona, Pellegrini now knows his City side must become the third team in Champions League history to overturn a first leg home defeat in order to continue his side's quadruple hopes which lie in tatters after a discouraging performance.

Despite Jose Mourinho taunting the four-time European Cup winners by labeling them among the worst teams to hail from the Nou Camp, manager Gerardo Martino was able to call upon eight former winners of the competition including Messi, fresh from his weekend double against Rayo Vallecano.

Opposite number Pellegrini opted for caution in City's first ever Champions League knock-out tie, selecting Aleksandar Kolarov on the left while Fernandinho was recalled from his three-week injury absence among six alterations from the FA Cup win over Chelsea.

The unfamiliar surroundings were further emphasised by the statistic that City were facing Barcelona in a competitive fixture for the first time, with the visitors aiming for their first win in Manchester in five trips to the north west.

If City's team selection had suggested caution, then their start to the game only worked to confirm the initiative they were willing to relinquish with Barca typically monopolising possession in the early stages though chances were at a premium.

Negredo was the hosts' only out ball in the first half in the absence of Sergio Aguero but the muscular fashion in which he held off Javier Mascherano before dinking towards goal suggested City could threaten if they embraced the Barcelona midfield.

And as the half wore on, City's physicality proved a greater factor and while it led to bookings for Negredo and Kolarov, it almost forced the opening goal but goalkeeper Victor Valdes was first fortunate to win a foul following a David Silva free-kick and then see Negredo shoot straight at him.

Though the Barcelona attacks were becoming less regular, they possessed additional potency, with Xavi warming Joe Hart's gloves with a stinging strike while Negredo's flicked header just before the break was another reminder of the aerial challenge the home side presented.

The second period began in identical fashion to the first, with the away side pinning City in the edge of their own penalty area and eventually the pressure told in the 54th minute as Messi broke in behind and was fouled inside the area by Demichelis, who was given a straight red card by referee Jonas Eriksson.

Replays suggested the original challenge may have occured outside the box but Messi was unperturbed by the controvercy, making no mistake from the spot as Barca grabbed a crucial away goal.

Barcelona did return to their metronomic passing self until City woke up and almost equalised as substitute Samir Nasri's shot was blocked though the home side were warned against a second half onslaught as Xavi blasted over and Alves drove wide.

Edin Dzeko replaced Negredo, a move which gave City added impetuous, as Silva's drive was impressively saved by Valdes.

But Barcelona were able to see out the game and even added a second through Alves' acute finish to secure a first leg advantage which swells their favourites tag ahead of the second meeting in three weeks time.