Dundee United manager Micky Mellon is delighted that goal hero Nicky Clark is giving him a selection headache.

Mellon opted to start with Lawrence Shankland and Marc McNulty as his front two against Motherwell on Boxing Day but Clark climbed off the bench to grab a vital injury-time equaliser in the 1-1 draw.

Clark displayed his goalscoring nous to take his tally for the campaign into double figures with a clinical and composed finish past Motherwell goalkeeper Trevor Carson after his initial shot had been blocked.

And Mellon is delighted to be able to call on experienced players like Clark, and fellow second-half substitute Peter Pawlett, as he knows they can make an impact from the bench.

Mellon said: "Nicky always gives me a headache. They all do to be honest. I have to try and pick the best team that I think will get us results.

"You want people to be coming on and giving you performances like that in order to get your results – you need quality all the way right throughout the group.

"I'm delighted for Nicky. He's a smashing lad who has come up trumps for us there. I was really pleased.

"I don't want to do a disservice to the young boys, because I trust them as well, but certainly to have that kind on experience and know-how, and be a wee bit clearer about what you might get when you are going to bring on someone like those guys, is certainly needed and that's what we were able to do."

Mellon felt Dundee United could have been awarded two second-half penalties for challenges on McNulty and Shankland but referee Bobby Madden waved away their appeals.

Mellon added: "We're not getting the rub of the green with those at this minute. I believe it was a stonewaller (the challenge on McNulty) and I think, as well, Lawrence Shankland nearly got his head wrestled off right at the end.

"If that's anywhere (else) on the pitch you get a free kick for that. But we crack on with that and we hope they go for us at some stage."

Motherwell manager Stephen Robinson hailed comeback goalkeeper Carson.

Northern Ireland international and Motherwell number one Carson was back for the first time since suffering a knee injury in a 4-0 win over Ross County in October.

Motherwell were the dominant side at Tannadice but Carson pulled off two great saves. In the first half he turned a Jeando Fuchs drive onto the post and then in injury time, moments after Clark's equaliser, he clinched the Steelmen a point with a wonderful stop to deny Adrian Sporle.

Robinson said: "Trevor is top class and his save in the first half was quality, as well as the one in injury time.

"When you are missing players like that at a small club, it certainly has an impact. That was one of the big pluses from the game, Trevor coming through."