Gary Harkins sent St Mirren on their way to the fifth round of the William Hill Scottish Cup after replacing the injured Paul McGowan before their 3-0 replay win over Queen of the South.
With McGowan in the stand wearing a protective boot on an injured foot, Harkins took less than 18 minutes to stroke home the opener from Steven Thompson's knockdown as Saints dominated the first half.
Derek Lyle volleyed against the bar before the visitors came back strongly at the start of the second period, but Thompson netted from close range in the 74th minute to set up a trip to Dundee United in February for Saints.
And left-back Sean Kelly rounded off the scoring with four minutes left when he netted a spectacular first goal for the club.
The victory followed a 2-2 draw at Palmerston, where Saints' League Cup defence came to a swift end in September, and it will give them confidence they can cope without influential playmaker McGowan if his absence proves lengthy.
His direct replacement, Harkins, did not take long to mark his first start since a 2-0 defeat by Hibernian on September 21 with his second goal since joining in the summer.
Thompson headed Kenny McLean's cross back into the goalmouth and, although Harkins failed to make proper contact, he had the time to cushion the ball home from inside the six-yard box with his second attempt.
The goal had an immediate impact on the former Dundee and Kilmarnock forward's confidence as he soon attempted to chip Zander Clark from just outside the centre circle - but the ball drifted just over.
Clark then saved McLean's 20-yard volley and Harkins soon looked lively on the right in a move that ended with John McGinn heading wide from a difficult chance.
Harkins had a decent chance to double his tally on the half-hour mark when Queens lost the ball from a throw-in near the halfway line. He bore down on goal from the left but curled wide from 20 yards.
McGinn caused panic in the home defence with a deflected cross which flashed across goal and his glancing header from Danny Grainger's cross soon drew a good diving stop from Clark.
But Saints almost suffered an unexpected blow six minutes from the break after they failed to deal with Daniel Carmichael's cross. David van Zanten headed the ball to the edge of the box with goalkeeper Marian Kello out of position and Lyle sent a flying volley off the top of the bar.
Queens immediately put Saints under pressure after the break. Iain Russell missed a good chance after Carmichael had got to the byline and then saw his deflected strike loop just over. Stephen McKenna headed wide and Lyle could not turn Ian McShane's free-kick home as they kept up the pressure.
But Saints gave themselves a two-goal cushion after passing up a couple of chances on the break. The goal had an element of fortune about it as Marc McAusland slipped while shooting after receiving the ball from Thompson 18 yards out. But his effort spun off a defender and fell kindly for Thompson to turn home from eight yards.
Marian Kello pulled off a stunning save to deny Lyle and Kelly, who had been rested from the start along with fellow full-back Jason Naismith, had the final say.
Harkins set him up 18 yards out to cut across the ball with his left foot and swerve the ball into the near top corner.