Inter, unbeaten this season under new coach Roberto Mancini, showed why before the interval as they continually caught Porto on the break and Obafemi Martins gave them a deserved lead. But Porto have not lost a European game at the Estádio do Dragão since it was transformed 12 months ago and Ricardo Costa claimed an equaliser their second-half performance merited.
 In his first European game, new Porto coach José Couceiro named Benni McCarthy with wingers Bosingwa and Ricardo Quaresma in a three-man attack, Derlei and Carlos Alberto having departed in the winter break. Captain Jorge Costa and teenage playmaker Diego were suspended. Up front for Inter, Adriano was partnered by Martins with Christian Vieri, recovered from injury, on the substitutes' bench. Alvaro Recoba and Edgar Davids were rested ahead of the weekend Milan derby.
 Porto, meeting Inter for the first time in their 250th UEFA club competition fixture, looked the more fluid side early on and Quaresma forced Francesco Toldo into action with an angled shot. Inter were having little time on the ball but a Juan Sebastián Verón free-kick allowed Marco Materazzi an 18th-minute header which Baía saved.
 However, Porto's forward motion often faltered when McCarthy found himself isolated and they fell behind midway through the half. Dejan Stankovic was the creator, conjuring a mazy dribble on the left and drawing Vítor Baía before crossing to allow Martins the easiest of tap-ins.
 Maniche immediately responded, his powerful long-range shot tipped over by Toldo. Porto then withdrew the limping Bosingwa for Luis Fabiano, but were on the defensive and Baía had to sprint 30 metres out of goal to intercept when Martins looked to send Adriano through. A superb Martins run then set up Verón to shoot over, while in a rare Porto incursion into the Inter box, Fabiano headed off target. The visitors were in control, Javier Zanetti an immense defensive presence.
 The holders were energised immediately after the break, launching series of strong attacks. The shots that came, though, were always from long-range and rarely dangerous. Inter were playing deeper than before half-time, while that meant Costinha had more room to prompt in midfield, the Porto attack was continually frustrated.
 Then, out of the blue almost, a breakthrough. On 61 minutes Nuno Valente curled in from the left and as Toldo grasped at air, Costinha at the far post squared and Ricardo Costa forced the ball in. The home team - and crowd - sensed a similar comeback to that against Manchester United FC in the opening game at the revamped Estádio do Dragão a year ago, but Inter were emerging from their self-imposed shell of the early second half, Stankovic having a strong shot blocked.
 So while Porto remained the main offensive threat, Inter began to again launch some swift attacks and Adriano went close before being replaced by Vieri in the final ten minutes. Fabiano then came near with an angled effort as Hélder Postiga was thrown into the mix - Porto were clearly intent on grabbing an aggregate lead.
 McCarthy so nearly did just that as he was sent clear on the right only to see his shot stopped at source when he cut back and Giourkas Seitaridis sent a strike over. Vítor Baía then stopped two close-range efforts to keep the tie level for the return.