Guarin goal gives Porto huge win
Substitute Fredy Guarin netted a late winner to give Porto a 2-1 win and put them in pole position in their Europa League last-32 tie with Iberian rivals Sevilla.
Guarin capitalised on a defensive mix-up five minutes from time to give Porto a potentially crucial advantage to take back to Portugal for the return leg.
Earlier, Porto had taken the lead through Jorge Rolando in the 59th minute but that was cancelled out by a Frederic Kanoute header seven minutes later.
Sevilla, UEFA Cup winners in 2006 and 2007, came into the match in poor domestic form with no wins in five matches, but the Spanish outfit edged a closely-fought first half.
Luis Fabiano, playing against his former club, was denied by a last-gasp tackle from Rolando when a goal looked certain, while Jesus Navas saw a deflected shot parried by Porto goalkeeper Helton.
The visitors, who won the 2003 UEFA Cup in the city of Seville, also went close with James Rodriguez's goal-bound volley beating the diving Andres Palop but being blocked by the head of Sevilla midfielder Gary Medel.
Porto were celebrating the lead 14 minutes into the second half though, when Rolando escaped his marker before flinging himself at Rodriguez's inswinging free-kick and diverting it past the helpless Palop.
The in-form Portuguese, who had won 29 of their 33 competitive matches this season and lost just once, were not ahead for long however, as Sevilla equalised soon after from a set-piece of their own, Kanoute doing well to glance Ivan Rakitic's free-kick past Helton from near the penalty spot.
Buoyed by that goal, Sevilla looked the more likely of the two sides to force a winner in the closing stages, with Luis Fabiano being denied by a great save from Helton, who also blocked Alvaro Negredo's shot at his near post.
Kanoute then fluffed a shot from three yards out with the goal at his mercy.
Porto were not without threat either though, and Hulk's thunderous 30-yard free-kick forced Palop into conceding a corner.
With time running out Porto got the goal that makes them favourites to progress through to the next round.
Sevilla will not want to see the replay of the incident too many times, as they first lost possession in midfield and then Sergio Sanchez left the ball, believing it had enough pace to get through to Palop, and Cristian Rodriguez was able to get there before the home goalkeeper.
Palop did well to dive at Rodriguez's feet and save, but the loose ball fell kindly for Guarin to slot into an empty net.
Sevilla came close to a late equaliser but Federico Fazio's downward header was parried by Helton.