Dundee United manager Mixu Paatelainen admitted he was surprised his side were so flat, given what was at stake at Tannadice last night.
The Tangerines crashed to a 3-0 defeat at home to Motherwell and look doomed as far as relegation goes.
They are now 13 points behind second-bottom side Kilmarnock with just 13 games to play, while Well moved 15 clear of them with this victory.
A header just on half-time from Stephen McManus was added to by a Scott McDonald double after the interval to really rub it in.
“It was not good enough,” said Paatelainen.
“It is as simple as that and that’s the bottom line.
“We were too flat and there was not enough urgency.
“There was also not enough quality, in certain situations.
“I was surprised considering what was at stake.
“It was a poor performance.
“We did realise and we highlighted it to the players that this it, this is a great opportunity.
“We said to them not to miss this opportunity but we did.
“The most disappointing thing is that it is not a 3-0 hammering as we lost two set-piece goals and we were poor and flat-footed.
“There was poor man-marking and that has been the story of our season.
“We had two clear-cut chances with John Rankin and Blair Spittal’s header and we simply had to score them.
“That is the recipe of defeat.
“It is not over yet as we will not give up.
“It is a long road ahead for us now.”