Race for the play-offs: How it all unfolded
6.31pm - The team news is in and as expected Martin O'Neill leaves Wes Hoolahan on the bench with Harry Arter, Robbie Brady and James McClean coming in for the Norwich play-maker, Callum O'Dowda and the injured Shane Long. Hal Robson-Kanu replaces Sam Vokes in Wales's only change.
7.05pm - Over in the RTÉ studio, the inevitable outrage at the dropping of Hoolahan begins. Eamon Dunphy says he is the "essential play-maker", Liam Brady reckons Hoolahan is "the one that makes the other lads play, all I can see is route one", while Richie Sadlier is hoping that O'Neill doesn't point to a 35-year old being asked to play two games in four days.
7.15pm - Right on cue, O'Neill explains his reasons behind dropping Hoolahan: "Two games in quick succession has obviously been a problem but he's raring to go. I thought he played excellently the other night but it's two games in quick succession."
7.45pm - After a powerful rendition of the Welsh national anthem, the time for talking is thankfully over. Jeff Hendrick gets the game under way in a rocking Cardiff City Stadium. Elsewhere in Serbia, the group leaders aim to avoid a slip-up against Georgia. Ukraine and Croatia's clash may be crucial as a draw for Wales could see them into the play-offs, if Ukraine-Croatia also finishes level and there are not more goals in Kiev than in Cardiff. Simply put, a win for Ireland and they're in the play-offs.
7.49pm - Early sight of goal for Wales as Robson-Kanu flashes a header wide. Ireland are struggling to get on the ball.
7.53pm - Darren Randolph is called into action and he does well as he tips Aaron Ramsey's shot over.
8.01pm - It's all Wales inside the opening quarter. Joe Allen is booked for a mistimed challenge on David Meyler.
8.08pm - Ronan O'Gara's tweet sums up what we've seen: "This is like Backs vs Forwards in GAA training back in the day!! Only 1 team allowed score." Hendrick meanwhile, scuffs a shot wide.
8.12pm - Ireland's passing accuracy is 20pc as we approach the half-hour mark. Wales's, in comparison, is 67pc. Grim reading.
8.16pm - The ball falls kindly for Shane Duffy but he drags his shot harmlessly wide.
8.22pm - Allen ships a knock and looks groggy. Wales are forced into an early change as Jonny Williams replaces him.
8.33pm - The half-time whistle sounds in Cardiff and it remains scoreless. Still no score in Serbia or the Ukraine either. As it stands, Ireland will not be going to the World Cup next summer.
8.40pm - "Woeful stuff", says Sadlier back in Dublin. Dunphy urges O'Neill to bring Hoolahan on as he senses a "big shock" is on the cards.
8.49pm - Wales get us going again in Cardiff. Huge 45 minutes.
8.54pm - James Chester comes close to breaking the deadlock as he heads into the side netting.
8.56pm - Randolph pulls off a stunning save to keep out Robson-Kanu's header. Ireland living on the edge now. Big moment.
9.0pm - GOALAZO! McClean to the rescue again. Brilliant from Hendrick to rob Ashley Williams of possession before he makes ground on the right. The Burnley man puts in a cross that is made all the better by a clever dummy from Arter and after that it's all about McClean's composure as he gives Ireland a precious lead with a right footed finish.
9.15pm - If Georgia can somehow nick a goal in Serbia, Ireland would be going to Russia as group leaders. Elsewhere, Croatia score two goals in eight minutes in Ukraine which means that a draw is now no use to Wales.
9.19pm - Nemanja Gudelj gives Serbia the lead which means they will win the group if the scores remain the same.
9.30pm - Clark and Shane Duffy have been immense at the back and continue to halt the wave after wave of red attacks.
9.37pm - Randolph pulls off another save, this time it was comfortable from Ramsey.
9.40pm - The full-time whistle sounds and another memorable night secures Ireland a play-off spot. O'Neill gets his selection spot on.