Goals from Dan Nlundulu and Jake Young helped St Mirren defeat Partick Thistle 2-1 to book their place in the Scottish Cup semi-finals.
It is a third appearance at Hampden this season for the League Cup winners, whose cup form stands in contrast to their struggles in the Premiership, where they sit 10th.
Ben Stanway’s second-half strike gave Thistle hope but the Championship side could not unearth a second goal that would have taken the tie to extra time.
Victory means St Mirren will face Celtic in the semi-finals in a repeat of the League Cup final, which Stephen Robinson’s team won 3-1.
St Mirren made two changes following their defeat at Dundee United. In came Declan John and Young, with Scott Tanser and Roland Idowu making way.
Thistle also made two changes from their goalless draw with Arbroath. Oisin Smyth was ineligible to play against his parent club and was replaced by Stanway. Ben McPherson came in for Luke McBeth.
Stanway almost made an immediate impression. Thistle won an early corner and, from the edge of the box, the midfielder’s effort struck a post.
St Mirren then did the same at the other end with Killian Phillips’ header also striking the frame of the goal.
Thistle then threatened twice in quick succession. Alex Samuel headed straight at Shamal George before Tsoanelo Letsosa’s driving run and shot also landed in the goalkeeper’s arms.
St Mirren’s Jake Young (L) celebrates scoring to make it 2-0
It was Saints, though, who forged in front after 33 minutes. Referee David Dickinson was called to the VAR screen to look at a potential handball offence against Robbie Crawford after the ball had ricocheted off the Thistle player’s foot and onto his outstretched arm.
The official decided that merited a penalty and Nlundulu beat Josh Clarke from the spot.
Saints continued to press and John saw a volley saved before Clarke also denied Miguel Freckleton and Young. In the midst of that action, the home side also lost Marcus Fraser, who went off with a shoulder injury.
That led to five minutes being added on at the end of the first half and St Mirren used it to plunder a second goal. Phillips won the ball from Patrick Reading before picking out Nlundulu. The striker then rolled the perfect pass for Young to thrash low past Clarke.
John shot into the side netting for Saints early in the second half, with Thistle replying with a Samuel effort that George did well to repel.
The visitors reduced the deficit with a fine strike after 61 minutes. Reading’s corner picked out Stanway on the edge of the box and his low volley found the net.
Thistle continued to push for an equaliser to take the tie to extra time and Samuel flashed a late header wide as Saints held on.
Celtic to face St Mirren in Scottish Cup semi-finals
Celtic will face St Mirren in the Scottish Gas Scottish Cup semi-finals.
The draw for the last four also pitted fierce rivals Dunfermline and Falkirk together.
Celtic will have the chance to avenge their Premier Sports Cup final defeat by Saints five months on from losing 3-1 to Stephen Robinson’s team.
The two games will take place at Hampden on the weekend of April 18-19.
