Ronny Deila displeased with Ryan McGowan tackle on Liam Henderson

Celtic manager Ronny Deila has accused Ryan McGowan of committing a "stupid" potentially career-ending tackle on Liam Henderson as the Dundee United defender was sent off near the end of Celtic's 4-0 Scottish Cup quarter-final replay win.

Goals from Jason Denayer, Leigh Griffiths and Kris Commons had put Celtic 3-0 ahead when home forward Anthony Stokes was dismissed in the 87th minute for lashing out at United midfielder Paul Paton.

Shortly afterwards, McGowan was also sent off for his challenge on Henderson in the corner before Virgil van Dijk made it 4-0 as Celtic secured a semi-final meeting with Inverness Caledonian Thistle on April 18 or 19.

Deila said: "It is stupid to tackle like that on the sidelines. We need to get that out of football.

"It is a youngster standing there with a little trick. You can either stay or go in with both feet, as I see it. You can injure him for life.

"But I have to see it one more time. He (McGowan) must be frustrated. That's why he did it.

"There were some angry and disappointed players. I spoke a bit to Stokesy. He got a knock in his mouth and was bleeding from the challenge with Paton and he reacted.

"I have to see it again to see if it was a red card. But I was delighted with the game."

United assistant manager Simon Donnelly's first thought was that McGowan's challenge was legal.

The former Celtic striker said: "I will need to see it again. I have only seen it at game time and it was a strong fair, challenge but I might be wrong.

"The Celtic reaction on the back of their player getting sent off maybe influences it but I will need to look at it again.

"Was it any worse than Scott Brown's tackle two weeks ago? (in the first Scottish Cup game)."

Celtic beat United 2-0 in the Scottish League Cup final at Hampden on Sunday when Tannadice skipper Sean Dillon was dismissed, adding to the three players - two from United - who were sent off in the first Scottish Cup match which ended 1-1.

The clubs meet again in the Scottish Premiership at Celtic Park on Saturday.