Celtic coped comfortably with the challenge of St Mirren to ease into the fourth round of the Scottish Cup.

The First Division side put up plucky resistance in the first half but Celtic stepped up a gear in the second period to stroll home.

Henrik Larsson pitched in with a double and Momo Sylla completed the scoring.

Celtic were missing several first team regulars, so Colin Healy and Jamie Smith were given a chance to show what they can do.

Republic of Ireland midfielder Healy, enjoyed a productive afternoon and his powerful running and willingness to get into the penalty box must have heartened manager Martin O'Neill.

Celtic turned up the heat in the second half

Smith also put in an eye-catching performance down the left flank on a day several of his big name team-mates failed to sparkle.

The home side were slow to get started and did not seriously threaten the Saints' goal during a dull opening 20 minutes.

When they eventually found some sort of rhythm, Celtic found visiting keeper Ludovic Roy in excellent form.

Chris Sutton almost opened the scoring when Smith picked him out at the near post with a corner, but was denied by a fantastic point-blank save by the Frenchman.

The Buddies came close to upsetting the odds when Martin Cameron capitalised on a slip by Joos Valgaeren but his shot was deflected into the side netting.

Healy should have scored moments later when the ball broke to him inside the box, but his shot came back off the upright.

Roy then pulled off two magnificent stops to deny Alan Thompson and Larsson to keep the score sheet blank at half time.

Maloney and Sylla celebrate goal no.3

The subdued crowd at Celtic Park did not have to wait long for a goal after the break with Larsson ghosting into the St Mirren penalty box and prodding home from a tight angle in the 47th minute.

Roy made two more impressive saves to deny Larsson and Smith before the prolific Swede doubled Celtic's lead in the 57th minute with a clever curling shot.

Substitute Shaun Maloney set up Celtic's third goal after 70 minutes when he found space behind the tiring Saints' defence and rolled the ball to Sylla who, despite a clumsy first touch, managed to trundle the ball calmly past Roy.

Sylla was denied a second goal by a goal-line clearance in the dying minutes.

Celtic: Hedman, Mjallby, Valgaeren (Crainey 71), Laursen, Sylla, Healy, McNamara, Thompson (Maloney 66), Smith, Larsson, Sutton (Fernandez 28).
Subs Not Used: Broto, Boyd.

Booked: Thompson.

St Mirren: Roy, Guy, Broadfoot, Denham, Baker, McGinty (Lowing 75), Murray, Gillies, Lappin (Robb 81), Mendes, Cameron (Dunbar 45).
Subs Not Used: Robertson, Yardley.

Booked: Denham.

Attendance: 29,976
Referee: C Richmond