Micky Mellon feels his Dundee United players will learn their lessons as they adjust to top-flight football after letting slip the lead in a 1-1 draw against 10-man St Johnstone.

Mellon looked set to get his United career off to a winning start in the Tayside club's first Scottish Premiership game in four years after Nicky Clark netted a sixth-minute penalty and Michael O'Halloran was sent off seconds before the half-time whistle.

But Lawrence Shankland squandered some openings just after the break and Craig equalised in style with a volley 10 minutes into the second half.

United took time to recover and could not test goalkeeper Elliot Parish as they put on the pressure late on.

Former Tranmere manager Mellon said: "When you go a goal up and the opposition goes down to 10 men and you have played the way you had done, you would expect as professionals to see it out.

"We just switched off in one moment of detail that we have worked very hard on. The players will know that. We were a wee bit loose when the ball got turned over and we get punished for that.

"Credit to St Johnstone, they dug in with 10 men, and then we have to go and break down a block, we kept prodding and poking away at it, but we just weren't able to undo a packed block.

"But we will learn our lessons and move on. That's what it's about, we are in a transition,  we have moved up a division.

"There are a lot of players who are playing at this level again for the first time in a long time or playing for the first time, as well as having a 17-year-old (Lewis Neilson) making his debut.

"We will gather the positives and move on to training next week and be ready to move the club on again."

St Johnstone are also under new management and Callum Davidson feared the worst before his team's unlikely comeback.

Saints fell behind after Craig was penalised for handball after blocking Liam Smith's strike.

"Obviously it was a bad start," Davidson said. "He gave the penalty decision and for 10-15 minutes we struggled a wee bit.

"We gradually came into the game and then the red card came and I thought 'oh, this is a good start'.

"I thought we were tremendous second half, I thought we were the better team. Shankland missed a chance early doors and I thought then we had a chance to get something out the game.

"You saw the energy levels and commitment and Danny McNamara's challenge late on typified the team."

O'Halloran was fortunate to escape a straight red card for his first booking following a foul on Peter Pawlett and walked a disciplinary tightrope before falling off with a late challenge on Callum Butcher.

Davidson said: "It was a sending off, no question about it. He got away with one five minutes before it and we were deliberating on the bench whether to take him off or leave him to half-time. We said 'leave it to half-time' then I turned round and he got sent off.

"Michael is desperate to do well. It's very hard to curb his enthusiasm and that discipline, it's a mixture of both. It's something he has got to learn."