The home side had started the game with great confidence, no doubt bellied by their recent wins over Bohemians, Drogheda and Bray. Bit O'Red 'keeper Richard Brush had to be at his best to deny a Thomas Stewart header from a Billy Dennehy cross after four minutes as The Hoops were showing that they meant business in this tie.
However, there was little he could do two minutes later when Twigg found the net after a telling pass from Chris Turner, as the big Scot controlled the ball perfectly before slotting low to the back of the Sligo net. This was an ominous early sign for Paul Cook's side, but they soon settled down and Gary McCabe went close after ten minutes when his shot from just outside the box whizzed past the left-hand upright.
Indeed, they went close again three minutes later when McCabe crossed from the by-line to the lively Joseph Ndo, but he failed to connect when the ball came in and the chance was gone. Sligo are always willing to have a go in any given game though, and this meant that the game was always likely to be fairly open.
Both sides would enjoy good spells of possession, but it would be The Hoops who would have the game's next real chance when former Sligo man Chris Turner unleashed a powerful shot on the spin, which produced a fine save by Brush. Ollie Cahill also went close on 31 minutes, but his miscued shot from 12 metres went harmlessly wide.
It seemed likely at this stage that Michael O'Neill's men would keep this one-goal advantage into the second half, but Sligo had other ideas and were back on level terms nine minutes before the break when former Hoops striker Padraig Amond finished clinically to the net after being put through by McCabe.
This silenced the passionate home support, and truth be told it was poor defending by the Tallaght men, who were caught napping at the back. This meant that the sides went in level at half-time and it was game on all of a sudden.
The Hoops suffered a blow just before the end of the opening period when the influential Chris Turner went off injured, to be replaced by Stephen Rice. This upset the balance of their midfield, and they did take a while to adjust to the change.
The match was very tight after the resumption, as both teams were aware of the threats that each other would pose if they were given the opportunity to attack. As a result, chances were hard to come by, although McCabe did have a glorious opportunity for Sligo on 58 minutes when he got the ball in space, but Mannus got down low to deny the pacy winger.
This was most definitely a missed opportunity though, and a goal here could have really shifted the momentum towards the Westerners. Instead, The Hoops started to come back into the game and Richard Brush pulled a fine save to deny Ollie Cahill after a mazy run.
The home side enjoyed the majority of possession in the final twenty minutes, even though McCabe went close again when he cut in from the left to unleash a right-footed that just breezed past the post. Sligo were on the back foot for much of the game's climax as The Hoops cranked up the pressure, but they held firm and go back to The Showgrounds with a hard-earned point.
Shamrock Rovers: Mannus; Murphy, Price, Murray, Flynn; Cahill (Barrett '72), Chambers, Turner (Rice '45), Dennehy; Twigg (Baker '59), Stewart.
Subs not used: Duggan, Stevens.
Sligo Rovers: Brush; Whelan, Peers, Keane, Ventre; Dillon (Doyle '83), Ryan, Doninger (O'Grady '72), McCabe; N'do, Amond (Blinkhorn '76).
Subs not used: McCartney, Kelly.
Referee: Damien Hancock.
Extra Time Man Of The Match: Gary McCabe (Sligo Rovers).