Jackson Martinez scored his first UEFA Europa League goal as Porto defeated Napoli 1-0 in the first leg of their last-16 clash.
Porto dominated for large parts of Thursday's game, but a combination of an incorrect offside decision that ruled out Carlos Eduardo's effort and the outstanding Pepe Reina frustrated them.
There was nothing Reina could do, though, to stop Martinez netting the only goal at the Estadio do Dragao after he reacted quickest to sweep home from 12 yards.
Martinez's 23rd goal of the season in all competitions means Porto travel to Italy for the second leg next week with high hopes of reaching the quarter-finals.
Porto ended a four-game winless run in all competitions at the weekend with a confidence-boosting 4-1 victory over Arouca and bossed the first half against Napoli with ease.
In what was the first European game in charge for interim coach Luis Castro, Porto would have been ahead early on but for a remarkable save from Reina.
Eduardo chipped a delightful ball to Martinez and he met it sweetly on the half-volley, but Reina showed great reflexes to tip away the shot.
The 2010-11 Europa League winners continued to have the best of proceedings, with Steven Defour next to sting the palms of Reina.
Castro's men should have been in front after 19 minutes when Martinez's inviting cross was nodded in by Eduardo, only for it to be incorrectly ruled offside.
The pattern of dominance continued in the early exchanges of the second half when Reina produced another superb stop to acrobatically claw away Fernando's rasping 30-yard drive.
Ricardo Quaresma scored two goals at the weekend and impressed again but his 50th-minute strike drifted wide.
Rafael Benitez is aiming to become the first manager to win the competition with three different clubs and his side finally showed some attacking intent after 52 minutes.
Napoli broke the offside trap and Jose Callejon set up Gonzalo Higuain, whose shot was low and powerful but went through Helton's legs and squirmed wide.
The Porto goalkeeper was in action again when Raul Albiol was left unmarked from a corner, but his low header was kept out by the feet of the Brazilian.
Helton brilliantly denied Higuain and the ball fell to Callejon six yards out, but he could not sort his feet out.
But the game swung Porto's way after 57 minutes when a corner was only half-cleared and Martinez showed great technique 12 yards out to lash home via a deflection.
It somehow stayed as 1-0 to the hosts with nine minutes remaining when Miguel Britos made a last-ditch tackle and his clearance from the floor cannoned straight off Juan Quintero and onto the post.
|Coach: Luís Castro|
for Carlos Eduardo 67'
for Silvestre Varela 72'
for S. Defour 87'
|Henry vows to help Arsenal after retirement|
|Everton can go far in Europe - Jagielka|
|Pardew expects Carroll return|
|Michu undergoes ankle surgery|
|Brandao sentenced to prison|
|Allardyce slams ´rather silly´ Tomkins|
|Rodgers similar to Wenger - Toure|
|J.League Preview: Flying Gamba chasing Urawa|
|Benitez happy to progress|
|Montella: Fiorentina have ´impressive mentality´|
|Pele ´doing fine´, receiving kidney treatment|
|Ausilio praises Handanovic´s ´remarkable statistics´|
|We need to improve - Stambouli|
|Estoril versus PSV postponed due to rain|
|UEFA Europa League Review: Feyenoord and Everton qualify in style|
|Martinez hails Everton perfection|
|Tottenham 1 Partizan 0: Stambouli settles it for Spurs|
|Inter 2 Dnipro 1: Osvaldo strikes as 10-man hosts earn hard-fought win|
|Tottenham-Partizan clash temporarily suspended due to pitch invasions|
|McKinlay named Moyes´ assistant|
|Poyet issues Chelsea challenge|
|Wolfsburg 0 Everton 2: Martinez´s men secure top spot|
|Lambert defends Bent loan move|
|Sunderland v Chelsea: Johnson eyes next major scalp|
|Riera released by Udinese|
|QPR v Leicester City: Pearson aiming to build on positives|
|Galatasaray and Anderlecht face disciplinary proceedings|
|Liverpool v Stoke City: Hughes plotting Anfield success|
|Vermaelen out for four to six months|
|Swansea City v Crystal Palace: Monk looking for positive response|
|Printant to remain Bastia head coach|
|Irvine knew nothing of Berahino drink-driving case|
|Pele admitted to special care unit|
|West Ham v Newcastle United: Allardyce pinpoints vital phase|
|Skripnik agrees three-year extension at Werder|
|Monk rubbishes talk of Michu return|
|FA charges Whelan over comments|
|Burnley v Aston Villa: Lambert laments list of absentees|
|Manchester United v Hull City: Bruce wary of in-form Rooney|
|Hughes hopeful over unwell trio|
|Grant named as Ghana coach|
|Bielsa expecting tough Nantes challenge|
|Basel charged by UEFA following pitch invasion|
|West Brom v Arsenal: Mertesacker refocusing attention after midweek win|
|Colaco banned by FIFA|
|Championship Preview: Derby head to happy hunting ground|
|Hertha Berlin v Bayern Munich: Hosts out to take advantage|
|Taylor injury ´not as bad as first feared´|
|Wilshere out for three months|
|Torosidis suffers calf strain|
|Malaga v Real Madrid: Ancelotti´s men in search of sweet 16|
|England climb FIFA rankings, Germany remain number one|
|Bolasie staying put - Warnock|
|Sewe Sport v Al Ahly: Ivorians eye more history|
|Schalke lose Matip with broken foot|
|Paris Saint-Germain v Nice: Ibrahimovic looks to end Ligue 1 goal drought|
|K. League Preview: Seoul, Steelers tussle for third|
|No complaints over FA charge for Allardyce|
|Redknapp ready for crucial run|
|Zapata targets regular first-team role at Milan|
|Fabregas revels in career-best form|
|Eriksen claims Tottenham struggling to ´connect´|
|MLS Preview: Schmid labels Galaxy ´physical´|
|Costa Rican Primera Division Review: Cartagines secure semi-finals berth|
|Serie A Preview: Roma out to stay in touch with Juve|
|The Strongest 1 Bolivar 1: Capdevila strike saves leaders|
|Sao Paulo 1 Atletico Nacional 0 (agg 1-1, 1-4 on penalties): Colombians reach final|
|Cruzeiro 0 Atletico Mineiro 1 (agg 0-3): Culpi´s men win first Copa do Brasil|
|Malmo´s Hareide furious with referee´s injustice|
|Dermendzhiev elated with Ludogorets display|
|Defour withdrawal stalled Anderlecht|
|Atletico achievement delights Simeone|
|Atletico did ´many´ things well - Michel|
|Raul Garcia promises no let-up from Atletico|
|Missed chances disappoint Rolfes|
|La Liga Preview: Real out to break club record at Malaga|
|Ancelotti praises defence after record-equalling win|
|Klopp: Arsenal deserved it|
|Peruvian Primera Division Review: Alianza Lima falter in Clausura race|
|Allegri targeting top spot after Malmo win|
|Rodgers pleased despite Ludogorets late show|
|Wenger rues Arteta injury|
|Ludogorets 2 Liverpool 2: More misery for Rodgers´ men|
|Malmo 0 Juventus 2: Tevez fires Allegri´s side closer to qualification|
|Anderlecht 2 Galatasaray 0: Mbemba secures third place for hosts|
|Bayer Leverkusen 0 Monaco 1: Ocampos strike stuns dominant hosts|
|Atletico Madrid 4 Olympiacos 0: Hat-trick hero Mandzukic books last-16 spot|
|Basel 0 Real Madrid 1: Ronaldo strike equals club record|
|Arsenal 2 Borussia Dortmund 0: Sanogo and Alexis seal progress|
|´We must believe´ – Villas-Boas wants Zenit progression|
|Bundesliga Preview: Schalke and Bayern out to bounce back from Euro setbacks|
|Jesus bemoans wasted Benfica chances|
|League Two Preview: Promotion rivals meet, leaders tackle basement club|
|Ligue 1 Preview: PSG and Marseille both fighting for top spot|
|Mitchell lands Tottenham role|
|Zenit 1 Benfica 0: Danny eliminates Portuguese champions|
|Deila concerned over Commons´ future|
|Everton quartet doubtful for Tottenham clash|
|Pochettino calls for extra rest|
|FA charges Everton and West Ham|
|Money not a factor for Van der Vaart|
|League One Preview: Bristol City out to stop the rot at Peterborough|
|Heldt: Chelsea hammering unacceptable|
|Mancini encouraged by Inter|
|Cheltenham appoint Buckle|
|Date set for Tonev appeal hearing|
|K. League Review: Steelers preserve advantage, Seongnam boost survival hopes|
|Moses out for several weeks|
|Drogba focused on claiming trophies|
|Bent makes Brighton switch|
|Kone included in Everton squad for Wolfsburg clash|
|Shaqiri can ´probably´ leave Bayern, says Beckenbauer|
|Ramsey backs under-fire Wenger|
|Fabregas clears the air with Ramos|
|Cavani urges Ligue 1 focus|
|Olsson out until new year|
|Sao Paulo´s Toloi confident ahead of second leg|
|Aguero our ´special player´, says Kompany|
|APOEL eye Europa League despite winless road streak|
|Silva disappointed by ´childish´ errors|
|Slutsky happy to keep ´intrigue´ alive|
|A-League Preview: Brisbane begin life after Mulvey|
|Eredivisie Preview: Ajax targeting improvement|
|Shakhtar did not lack motivation - Shevchuk|
|Bayern lament two errors, Guardiola proud|
|Valcke: It will ´take years´ to rebuild FIFA´s reputation|
|Luis Enrique ´never fed up´ of Messi magic|
|Valverde pleased with Bilbao triumph|
|Messi revels in Champions League milestone|
|Loss was a ´crying shame´ - De Boer|
|Suarez relieved to get off the mark for Barca|
|Pellegrini puts Aguero among best in the world|
|Cavani wants top spot|