Celtic maintained their Treble aspirations with a comprehensive win over Dundee United in their Scottish Cup quarter-final replay.

Goals from Jason Denayer, Leigh Griffiths, Kris Commons and Virgil van Dijk teed up a semi-final appearance against Inverness Caledonian Thistle at Hampden.

In keeping with the tone of the past two meetings between the sides in the last 10 days, there were red cards, too, this time for Anthony Stokes and Ryan McGowan as the game drew to a close.

Stokes was dismissed for kicking out at Paul Paton, although as he left the field he claimed he had been elbowed by the United player.

Minutes later, McGowan sparked an angry melee among both sets of players when he booted Celtic sub Liam Henderson up in the air.

United had welcomed Nadir Ciftci back into the starting line-up after the Turkish midfielder had been suspended for Sunday's League Cup final which Celtic won 2-0, but he was unable to give Jackie McNamara's side any real impetus in an attacking sense.

Celtic showed little hangover from their cup celebrations and, from the early stages, played with a vim and verve that always suggested they would ease their way through to the next round.

When teenager Denayer headed them into an early lead, any passage back into the tie for United looked unlikely.

The attacking quartet of Commons, Stokes, James Forrest and Griffiths gave Celtic an energy and pace that United found difficult to cope with.

Time after time the visitors lost possession and found themselves floundering under repeated waves of Celtic attacks.

Inevitably, Celtic added to their lead as the game drew on. Griffiths, playing with a confidence that comes with finding the net on a regular basis, scored the goal of the night when he converted Scott Brown's long ball over the top of the visiting defence.

Celtic continued to press and got their reward, with Commons adding a third. Van Dijk set the seal with a fourth.

It was a scoreline that did not flatter Deila's side, whose momentum could carry them towards only their fourth Treble in the club's history.