Inverness CT 0-5 Dundee United

Dundee United blew nine-man Inverness away to storm into the Scottish Cup semi-finals.

Nadir Ciftci took advantage of comical defending to grab the first two, before Gavin Gunning fired home a penalty.

Greg Tansey was sent off before half-time when his studs caught the top of Paul Paton's foot.

Gary Mackay-Steven and Stuart Armstrong added further strikes, followed by a second red card for the hosts when Marley Watkins was also sent packing.

The Tangerines - last winners in 2010 - join Aberdeen and St Johnstone in Sunday evening's semi-final draw, and also erased memories of October's controversial Scottish League Cup defeat in the Highlands.

Inverness, meanwhile, have now conceded ten goals in their last two games, and need to re-find their form quickly with the League Cup final against Aberdeen just seven days away.

With the game crying out for inspiration after a dull opening, Dundee United produced it.

Ciftci (centre) capitalised on poor Inverness defending to net two goals

John Rankin picked out Ciftci with a neat lob forward and, with Josh Meekings struggling to close him down, the Turk was able to nod the ball past Dean Brill and slot into the net.

It was great skill from the United striker, but Inverness had not defended the long ball well after David Raven gifted possession in midfield.

The goal sparked the game into life. Tansey flighted in a free-kick which Gary Warren was able to nod into the path of the ever-dangerous Billy McKay, but he headed over from close range.

If the opening goal had been defended poorly, United's second was a catalogue of errors.

Meekings' pass-back held up in the mud, but Brill looked like he had rushed out in time to deny Ciftci. However, the goalkeeper cannoned his clearance off the defender, allowing the United striker to latch onto the loose ball and knock it into the empty net.

Inverness full-back Graeme Shinnie had a shot saved before Keith Watson was denied from close range at the other end, but John Hughes' men kicked themselves in the foot again to all but hand the visitors a place in the last four before half-time.

Shinnie took the back of Gunning's legs inside the area, sending the centre-back sprawling in the box. The Irishman took the penalty himself, rocketing his shot down the middle.

The half-time whistle could not come quick for the hosts, but the misery continued as Tansey was given a straight red card by referee Willie Collum for his lunge at Paton.

If the Highlanders were to have any hope of keeping alive their cup dreams they simply had to score next, and Shinnie burst through the middle past Ryan Dow and Rankin before unleashing a swerving shot that Radoslaw Cierzniak did well to push away.

However, within four minutes of the second-half Dundee United had the game wrapped up. Armstrong picked out Mackay-Steven wide on the left wing, and the winger raced clear before firing the ball in off the far post.

United were now rampant. Watson picked out Armstrong in the middle and he directed his header beyond Brill to add a fifth.

The day continued to get worse for Inverness. Watkins saw red when he caught Paton with a late challenge. It was perhaps harsh on the home side, with Paton himself earlier given a reprieve for a similar challenge on McKay.

Substitute Brian Graham twice fired over in the latter stages but United could not add a sixth, as they booked a place in one of next month's semi-finals at Ibrox Stadium.