Match ends, Republic of Ireland 0, Portugal 0.
The Republic of Ireland's encouraging recent form continued as they drew their World Cup Group A qualifier with a sub-par Portugal in Dublin.
Cristiano Ronaldo had a frustrating night for Portugal, who saw Pepe sent off late on for two bookable offences.
Chiedozie Ogbene and Enda Stevens spurned chances, while Matt Doherty had a goal disallowed near the end.
With the Republic's qualifying hopes already over, Portugal are tied on 17 points with Serbia with one game left.
Having looked on course for a famous win in Faro in September only to be sunk by Ronaldo's late double, the Republic had revenge on their minds in front of a noisy 50,737-strong crowd inside the Aviva Stadium.
Pepe's 82nd-minute dismissal - the Porto defender earning a second yellow card for catching Callum Robinson with a stray elbow - offered the hosts a chance to earn a late win.
- Republic of Ireland 0-0 Portugal: as it happened
- Kenny unhappy over disallowed goal as he lauds Republic display
They had the ball in the back of the net in injury time, too, but Doherty's celebrations were cut short by the referee's whistle after Irish debutant Will Keane was adjudged to have fouled Rui Patricio.
Portugal boss Fernando Santos arguably had one eye on Sunday's crunch game against Serbia with Manchester City pair Ruben Dias and Joao Cancelo and Liverpool's Diogo Jota among those to be left on the bench.
And while Republic boss Stephen Kenny will be heartened with a clean sheet against a side of Portugal's potency, the 2016 European champions must deliver a point at home against the Serbs in order to seal automatic qualification for next year's finals in Qatar.
Battle of the two CR7s
The danger men for both sides came into the game on the back of hat-tricks. Ronaldo had bagged his 10th hat-trick for Portugal against Luxembourg and Robinson - the Republic's own 'CR7' - hoping to build on his first international treble in the Republic's friendly win over Qatar.
Ronaldo endured a difficult first half, however, as he was foiled twice by returning Republic captain Seamus Coleman, who showed impressive recovery pace to land a last-ditch sliding challenge on the 36-year-old before charging down the Manchester United forward's first-time shot after Goncalo Guedes' pass.
Portugal also had tentative appeals for a penalty waved away when Ronaldo was challenged by Doherty while contesting an aerial ball. That led to a swift Republic counter, although Robinson was unable to trouble Patricio sufficiently after cutting inside from the left flank.
With five goals in his past two Republic outings, Robinson was easily the home side's most dangerous player throughout the opening 45 minutes, also creating a chance for Ogbene who was unable to direct his near-post header on target after being found by the West Brom attacker.
Ronaldo's best chance arrived midway through the second half when he was picked out by a pinpoint Andre Silva cross from the right, but after sneaking in between Jeff Hendrick and Coleman, the former Real Madrid man glanced his header inches wide with Gavin Bazunu beaten.
Bazunu was helpless again on 79 when Ronaldo uncorked a right-footed shot from the edge of the area, with the young Republic keeper relieved to watch it sail just wide of his left-hand post just moments after Stevens had failed to keep his shot down at the other end having been found by Ogbene.
Portugal looked nervous at the back at times, most notably when Matheus Nunes ran into trouble inside his own box before slipping, but Josh Cullen could only curl his shot into Patricio's grasp.
Earlier, Patricio had come to Portugal's rescue when he raced 30 yards from his line to deny Ogbene, who looked favourite to connect to a ball over the top and test the Roma stopper in a one-on-one.
It is another encouraging result for Kenny, whose side have responded to that late heartache at the hands of Ronaldo in Faro by embarking on a five-game unbeaten run.
It is also a third clean sheet in a row for the Irish and Kenny will be pleased with how his three centre-halves - in particular Coleman - thwarted Ronaldo and his United team-mate Bruno Fernandes, who was a peripheral figure before he was taken off with 15 minutes left.
Having salvaged some pride after a disastrous start to the campaign, Kenny hopes to end the qualifying series on a high by exacting revenge on Luxembourg as the 50-year-old looks to seal a contract extension before his current deal runs out next summer.
The Republic conclude their campaign with Sunday's trip to Luxembourg, who stunned the Irish with a 1-0 win in Dublin in March, while Portugal host Serbia, who warmed up for that critical game with an easy 4-0 win over Qatar.
R. of Ireland
- 2ColemanBooked at 54mins
- 13HendrickSubstituted forHourihaneat 78'minutes
- 3StevensSubstituted forMcCleanat 78'minutes
- 20OgbeneBooked at 29minsSubstituted forKeaneat 90+1'minutes
- 7RobinsonBooked at 90mins
- 18McGrathSubstituted forIdahat 61'minutes
- 1Rui Patrício
- 2Nélson Semedo
- 3PepeBooked at 81mins
- 13DaniloBooked at 70mins
- 19Alves Palhinha Gonçalves
- 10NunesSubstituted forJoão Moutinhoat 57'minutes
- 11Bruno FernandesSubstituted forRenato Sanchesat 75'minutes
- 17Gonçalo GuedesSubstituted forda Conceição Leãoat 56'minutesSubstituted forJosé Fonteat 83'minutes
- 9André SilvaSubstituted forSequeiraat 75'minutes
- 7Cristiano Ronaldo
- 4Rúben Dias
- 6José Fonte
- 8João Moutinho
- 12Malheiro de Sá
- 14William Carvalho
- 15da Conceição Leão
- 16Renato Sanches
- 22Meireles Costa
- Jesús Gil Manzano
- Shots on Target
Second Half ends, Republic of Ireland 0, Portugal 0.
Attempt saved. Cristiano Ronaldo (Portugal) right footed shot from a difficult angle on the right is saved in the bottom right corner.
Rui Patrício (Portugal) wins a free kick in the defensive half.
Foul by Will Keane (Republic of Ireland).
Attempt blocked. Matt Doherty (Republic of Ireland) header from the centre of the box is blocked. Assisted by John Egan with a cross.
Callum Robinson (Republic of Ireland) is shown the yellow card.
João Félix (Portugal) wins a free kick on the left wing.
Foul by Matt Doherty (Republic of Ireland).
Substitution, Republic of Ireland. Will Keane replaces Chiedozie Ogbene.
Hand ball by Chiedozie Ogbene (Republic of Ireland).
João Félix (Portugal) wins a free kick in the attacking half.
Foul by Josh Cullen (Republic of Ireland).
Attempt blocked. Matt Doherty (Republic of Ireland) right footed shot from outside the box is blocked. Assisted by Conor Hourihane.
Attempt missed. Adam Idah (Republic of Ireland) header from the centre of the box is close, but misses to the left. Assisted by Callum Robinson with a cross.
Attempt blocked. Callum Robinson (Republic of Ireland) right footed shot from outside the box is blocked.
Foul by Renato Sanches (Portugal).
Séamus Coleman (Republic of Ireland) wins a free kick in the defensive half.
Substitution, Portugal. José Fonte replaces Rafael Leão.
Second yellow card to Pepe (Portugal) for a bad foul.