Yaya Toure has warned his Manchester City teammates that they still have work to do to reach the Europa League's last 16 stage.

The Premier League leaders start tonight's last 32 second-leg tie as favourites to progress against holders Porto after securing a 2-1 advantage in Portugal.

But Toure does not expect Porto to relinquish their Europa League crown without a fight at the Etihad stadium. City's Ivory Coast international said Roberto Mancini's men would have to play as well as they did in the first leg if they were to progress.

"We'll have to play well again because the second game will be the same, very hard, although we'll have the advantage of playing in front of our fans. Porto have fantastic players and it will be difficult, but we have to keep going and go through in this competition," said the former Barcelona midfielder.

Argentina international striker Sergio Aguero could start for City after coming off the substitutes bench to score a dramatic late winner in the first leg at the Estadio do Dragao. Mancini's side had trailed to a Silvestre Varela goal before Alvaro Pereira scored an own goal to level the tie.

City are refreshed ahead of the deciding leg after a rare weekend without a game as they were knocked out of the FA Cup in the third round.

Meanwhile, Porto arrive in Manchester on the back of a 3-1 domestic away win at Vitoria Setubal which moved them to within two points of leaders Benfica.

Porto midfielder Lucho Gonzalez feels confident he and his team-mates have what it takes to overturn the deficit.

"Obviously it's not positive when you lose at home in a two-legged tie, but we have what it takes to travel to Manchester and beat them.

"All City's players have loads of quality, so you have to remain focused for the entire game."

Porto can draw encouragement from the fact that City have lost twice at home this season in domestic cup competitions.

But the visitors are not helped by the absence of highly rated Danilo due to a knee injury.