Niall McGinn admits Celtic cannot afford any more slip-ups if they are to catch Rangers in the SPL title race.
The Bhoys have slipped nine points behind their fierce rivals after being held to a 1-1 draw by basement boys Falkirk.
Celtic travel to St Johnstone this Sunday, live on Sky Sports 1, knowing they need to go on a winning run to close the gap on Rangers.
McGinn, who scored the winning goal in the midweek Scottish Cup victory against Morton, knows they need to keep the pressure on Rangers by taking all three points in Perth.
"We cannot afford to drop any more points and we need to go on a winning run to close the gap on Rangers," McGinn told skysports.com.
"We need to put pressure on Rangers and the next Old Firm game will be a must-win game for us."
McGinn is hoping his goalscoring performance against Morton will be enough to earn him a starting spot against St Johnstone.
"It was good to score on Tuesday night and hopefully I will keep my place in the team for this weekend's game," added McGinn.