Tangerines hit for six
Sat 16th Feb 3pm
Dundee United took an early lead before eventually crashing to a 6-2 defeat as manager Jackie McNamara experienced a disappointing return to former club Celtic.
Midfielder Stuart Armstrong earned the visitors a tenth-minute advantage after Gary Mackay-Steven had stolen possession from Charlie Mulgrew.
But Efe Ambrose immediately headed an equaliser from a corner delivered by Kris Commons, who then thumped in a second off the crossbar to give his side the lead.
Skipper Jon Daly should have levelled from the spot after Mackay-Steven was fouled by Adam Matthews moments later, only for goalkeeper Fraser Forster to block his penalty.
Celtic still went further in front ahead of the break with a deflected effort from Joe Ledley before Commons' spot-kick made it 4-1 after Barry Douglas had caught Anthony Stokes early in the second-half.
Stokes duly increased the lead with an emphatic twenty-yard conversion with twenty minutes remaining before then making it six after goalkeeper Radoslaw Cierzniak had initially denied James Forrest.
The visitors at least completed the scoring through Johnny Russell's low finish in the final minute - but that was prove little consolation in a first heavy defeat for their recently-appointed boss.
Celtic: Forster, Matthews, Ambrose (Kayal 71), Wilson, Izaguirre, Ledley, Wanyama (Forrest 76), Mulgrew, Commons (Rogic 73), Stokes, Hooper
subs (unused): Zaluska, Rogne, Miku, Lassad
Goals: Ambrose (11), Commons (22, pen 55), Ledley (37), Stokes (70, 82)
Dundee United: Cierzniak, Watson, Dillon, McLean, Douglas, Flood (Ryan 38), Rankin, Armstrong, Mackay-Steven, Russell, Daly (Gardyne 78)
subs (unused): Banks, Soutattar, Millar, Petrie, Dow
Goals: Armstrong (10), Russell (90)