Celtic responded well to their 2-0 home defeat to Kilmarnock on Saturday by routing St Johnstone 5-0 in the Scottish League Cup.
Kris Commons was the man who sparked Neil Lennon’s side in Tuesday’s quarter-final clash, bagging two goals by just after the half-hour mark, while a 38th-minute Gary Hooper strike made it 3-0 to Celtic at the half-time break.
It was more of the same after the interval, with Commons scoring a penalty on 57 minutes, and when Charlie Mulgrew scored just after the hour mark Celtic had wrapped up a comfortable victory to secure their spot in the semi-finals.
In the other quarter-final match on Tuesday, St Mirren defeated Aberdeen on penalties after scores were locked at 2-2 following extra time.
Sam Parkin opened the scoring after six minutes for the Saints at Pittodrie, but Scott Vernon hit back for the home side to tie things up.
Kenny McLean restored St Mirren’s's advantage on 69 minutes, but Josh Magennis scored in the 92nd minute to send the match into extra time.
With neither side able to break the deadlock it was left to penalties to decide the outcome, with the visitors holding their nerve better in the shootout.