PSV Eindhoven defender Hector Moreno is "so sorry" after his tackle led to Manchester United left-back Luke Shaw suffering a serious injury.
Shaw, 20, was stretchered off in the first half of United's 2-1 Champions League loss to PSV on Tuesday night following a challenge from Moreno.
The England international has since been diagnosed with a double fracture in his right leg, meaning he faces a lengthy period on the sidelines, and he underwent surgery on Tuesday night.
Moreno himself suffered a broken leg while playing for Mexico against Netherlands in the 2014 World Cup, so can understand the agony of such a setback.
"I feel really sorry," Moreno said. "I just feel really bad because I was involved in the accident."
First of all I wanna send my strenght to @LukeShaw23 I've been through this before and I know how it feels.. So I hope a fast recovery 1/2
- Hector Moreno (@HectorMorenoh) September 15, 2015
For you and see u again on the field. All the best. 2/2
- Hector Moreno (@HectorMorenoh) September 15, 2015
A United statement read: "Luke Shaw underwent surgery on his injury on Tuesday night and will remain in hospital in Eindhoven to continue his early recovery.
"Manchester United are grateful for the excellent care he is receiving and would like to thank everyone who has sent messages of support.
"A further update will be provided in due course."
Moreno was not penalised for the tackle by referee Nicola Rizzoli, and the Mexican said he did not believe he had fouled Shaw.
"I think not," he said. "I think I played the ball, but in this kind of situation I don't care if it was a foul -- I feel bad for him, and for his family.
"I don't know how bad it is, but I had myself a situation like that during the World Cup and it's bad.
"It's difficult to say what happened. Now I just hope he will be back as soon as possible."
Defeat hurts, but @LukeShaw23's injury hurts even more. We hope you come back even stronger!
- David De Gea (@D_DeGea) September 15, 2015
Former Premier League official Graham Poll feels Rizzoli was wrong not to send the centre-back off.
He said in the Daily Mail: "Italian referee Nicola Rizzoli couldn't have saved Luke Shaw from breaking his leg on Tuesday night but he could and should have punished PSV defender Hector Moreno.
"Moreno should have been reprimanded for the terrible tackle which caused Shaw the horrific double fracture of his leg.
"Moreno showed no regard for his opponent's safety when he flew in to tackle Shaw as the Manchester United defender burst into the PSV penalty area.
"His leading leg might have touched the ball but the way he entered into the challenge -- at pace and off the ground -- he had no control over his actions.
"Rizzoli knows the law and, while the tackle might have looked worse in slow motion replays which the referee does not see, he should detect and punish such tackles made with excessive force.
"He is one of UEFA's very best officials but he missed a poor tackle here which also should have resulted in a penalty for United as well as the red card for Moreno. That the Mexican then scored the equaliser really did highlight what a costly mistake the referee made."
My thoughts and prayers are with @LukeShaw23 Hoping for a quick recovery and to be playing alongside him again as soon as possible! ����
- Chris Smalling (@ChrisSmalling) September 15, 2015
United manager Louis van Gaal said: "When I say it's a penalty and a red card, I'm a bad loser. It was a bad tackle with two legs. Every word I say is one word too much."
On how long Shaw would be sidelined, he added: "I am not a doctor so I cannot say that but when you have a double leg fracture it is six months. He will not play in the group phase I think but I hope he can play again this season."
Information from the Press Association was used in this report.