Hopes ended for ten-man United
Sun 11th Mar 1.15pm
The first-half dismissal of Robbie Neilson proved decisive as holders Celtic scored four times without reply after the break to send ten-man Dundee United out of the Scottish Cup at Tannadice.
Neilson had already been booked by the time he went in to challenge Georgios Samaras and was adjudged to have used an elbow - which earned him a straight red card.
The Tangerines had earlier shown well with Jon Daly heading a Willo Flood cross wide and Celtic keeper Fraser Forster superbly denying Johnny Russell following Gary Mackay-Steven's assist. Mackay-Steven was soon to be sacrificed after Neilson's dismissal.
For the visitors, James Forrest shot wide in reply until they went ahead after Daly had seen a low drive held by Forster at the start of the second-half; Welsh international Joe Ledley turning Anthony Stokes' 53rd minute cross beyond Dusan Pernis.
Home substitute Milos Lacny then proved wayward from the edge of the area after replacing Gavin Gunning before Charlie Mulgrew immediately swept over a free-kick and Samaras rose highest to head in number two.
Russell soon struck another effort wide but it was the visitors who should have extended their lead when Stokes missed an open goal after crashing his shot against the crossbar following excellent work by Forrest.
However, Stokes made no mistake as he collected Ledley's 86th minute pass and steered in a third before Scott Brown added a last-minute penalty after Sean Dillon was penalised for a challenge on Samaras inside the area.
Dundee United: Pernis, Neilson, Dillon, Gunning (Lacny 59), Dixon, Flood (Armstrong 78), Robertson, Rankin, Mackay-Steven (Kenneth 30), Daly, Russell
subs (unused): Banks, Ryan
Celtic: Forster (Zaluska 90), Matthews, Rogne, Mulgrew, Ledley, Brown, Wanyama, Forrest, Samaras, Stokes (Commons 88), Hooper (McCourt 81)
subs (unused): K, Wilson, Cha Du-Ri
Goals: Ledley (53), Samaras (71), Stokes (86), Brown (pen 90)