Last update on. From the section Scottish League Cup
Ali Crawford, an on-loan Bolton midfielder, sealed the win with his first St Johnstone goal late in the game.
League Cup holders St Johnstone advanced to the third consecutive semi-final, after Shaun Rooney scored after the break and Ali Crawford won at Dundee.
Rooney, who won the Tayside cup finals with winning headers, won the tie on 70 minutes. Crawford added another late.
Callum Davidson's team will face their semi-final opponent Thursday. This will be Hampden's fifth appearance in less than a decade.
It is now four games with no goals in all competitions for Dundee and more than 15 years since their last visit to the national stadium, a semi-final loss by Gretna in the Scottish Cup in April 2006.
James McPake's men wanted to end a 15 year-old hoodoo while Davidson's team was determined to keep their League Cup title.
The hosts almost got the upper hand, as Zander Clark was alert to grab the ball off the line following a Dundee corner hit by defender Jamie McCart.
Visitors posed a threat of their own. Adam Legzdins was forced to tip an attempt by David Wotherspoon.
The tie continued to flow as Cammy Kerr and Jordan McGhee had saves from close range headers. A Glenn Middleton volley was also saved up the other end. Leigh Griffiths couldn't capitalize on a poor Rooney pass back.
Despite both sides troubling their keepers, the half ended goalless. The second half began in a similar fashion. Griffiths had Clark at full stretch trying to take away a free kick, while McMullan was scuffing the rebound.
Griffiths was unable to stop the ball from falling, as the Celtic striker on loan made a right-footed attempt.
It was actually a swipe of Rooney's right foot to the side that broke the deadlock. Rooney lost the ball in a corner and the ball fell to Rooney. Rooney turned and rolled in a controlled finish with a slight deflection.
Dundee tried to score an equaliser but was stopped by a strong visiting defence. It was that defense member who set up the second goal for St Johnstone. Callum Booth sent a ball across to Crawford, and Crawford managed to guide it in a neat finish.
Zander Clark is the man of the match
The Scotland goalkeeper has been in great form and pulled off some amazing feats before the opener to keep his side on level.
What have we learned?
McPake would have hoped Griffiths would come in to Dundee to complete the attack.
It is now four games with no goals - 367 minutes since their last strike. They will need to forget about their cup loss and focus on the Premiership survival.
St Johnstone's season has a certain deja vu quality. They began poorly last season before their League Cup push revitalized their campaign.
After a first league win at Aberdeen, a quarter-final victory at Dens Park was followed - a 15th cup tie undefeated. Now the question is whether this can be used to launch the remainder of their campaign.
What were they saying?
James McPake, Dundee manager: "I sound like a broken record." We are taking clear-cut chances and not just wasting chances. It's a problem.
These are the important things that will make the difference between you winning the league game or the cup. They are being created, which is a plus. But that can only be said for so long.
Callum Davidson, manager at St Johnstone: "It wasn't an easy game. Dundee gave it their all, and so did we. We had slightly better chances but they were slightly out of it.
"That's why Ali [Crawford] came in, for that attacking side. He gives us that extra dimension. Shaun [Rooney] seems like he turns up and scores these goals at just the right moment. We hope that this can continue.
What's next?
Dundee hosts Rangers in Saturday's Premiership (15:00 BST), while St Johnstone travels to Hibernian on the next day (15:00).
