Frazer Wright and Francisco Sandaza scored their first St Johnstone goals as they knocked Livingston out of the Scottish Communities League Cup.
Wright got the final touch to put Saints ahead after a scramble in the box at a corner.
Sandaza fired home with a superb shot in the 18th minute and added another strike seven minutes later.
Livi's Iain Russell could have set up Keaghan Jacobs for a consolation but shot himself and missed the target.
Having claimed their first win of the season at Celtic Park on Sunday, Derek McInnes's side started the match in confident fashion and Murray Davidson flashed a header wide.
Livi goalkeeper Andrew McNeil spilled a cross to give the hosts a corner and, from debutant Willie Gibson's delivery, Wright bundled home his first goal for the McDiarmid Park club.
Cillian Sheridan fired wide before Liam Fox drew a save from St Johnstone keeper Peter Enckelman.
Sandaza's excellent turn and shot from Gibson's pass stretched Saints' lead and the Spaniard slotted home the third after being set up by Sheridan.
Wright and Davidson were withdrawn due to injury during the first half, Alan Maybury and David Robertson their respective replacements.
The visitors improved in the second period and Russell fired wide instead of passing to the better placed Jacobs before Marcus Haber and Gibson were off target with further efforts for Saints.
St Johnstone manager Derek McInnes on two-goal Francisco Sandaza: "He is an instinctive striker, a selfish striker, he wants to score goals and he wants to go and affect the game.
"Some of his link-up play in the first half was excellent and he isn't afraid to have a shot at goal.
"As soon as he turned for the second goal you felt he was going to score and that is something great for the team as well to have that at the top of the pitch.
"He is still getting there with his fitness but he's had that 90 minutes in the bag now and we'll see how he gets on against Dundee United on Saturday."