Inverness manager Richie Foran laid the blame for his side’s defeat at the door of his players and assistant referee David McGeachie.
The official made a huge call in the 65th minute when he judged that a Scott McDonald header from point-blank range had crossed the line to give the Steelmen a 3-2 lead.
Foran, whose side are now seven points adrift of yesterday’s opponents, has no doubt that the decision was the pivotal moment of this contest. “I couldn’t see it; I was as far away as the linesman who gave it,” he said. “My players are adamant it hadn’t crossed the line.
“One of their players, who was right beside it, has just told me it definitely didn’t go over the line. It kills us. The linesman made a decision. You’ve got to be 100 per cent correct and he was obviously wrong. He has played a big part in the outcome of this game.
“This won’t affect the linesman. He isn’t going to phone me during the week and apologise. He’ll just get on with it. He’s made a mistake and doesn’t understand the consequences for us. Maybe he doesn’t care, I don’t know. I don’t know him personally. Look how far away he is. I think you can tell by the body language of players as well.
“At this stage of the season, it’s a big decision. Maybe he wants to make a name for himself but it’s disappointing. It’s an unbelievable decision.”
It was a match both sides needed to win but the hosts looked the hungrier from the outset and two early goals knocked the Highlanders out of their stride.
When Chris Cadden picked up a pass from Allan Campbell on the right flank there seemed little danger. However, the Inverness defence parted like the Red Sea as he cut inside and, although he was forced to use his less favoured left foot, Cadden placed his shot inside the far post from the edge of the penalty area.
Two minutes later the Lanarkshire club doubled their advantage after more comedy defending. Louis Moult’s deep cross should have been collected by Owain Fon-Williams but, under pressure from Ryan Bowman, the goalkeeper flapped at the ball as it arced over him and under his crossbar.
“To go two goals down like we did was embarrassing,” said Foran. “The first one — show the wide man down the line, like you tell ten-year-olds. Instead, he comes inside and bends one in.
“The second one – a cross is hung, your goalkeeper doesn’t come and catch. I don’t think there’s anything I can do about that. It’s down to the players. I can’t take a lot of blame for this.”
Motherwell ought to have put the game to bed shortly afterwards when Fon-Williams spilled a shot from Moult and Bowman drove the rebound straight at the Welshman.
Inverness appeared to be dead and buried but, with a dollop of good fortune, they found themselves back in contention. Liam Polworth’s wayward shot would not have troubled Craig Samson but Alex Fisher had the presence of mind to stick out a foot and divert it inside his left-hand post.
After that it could have been anything, with a multitude of opportunities at both ends.
Fon-Williams partially atoned for his previous gaffe with a superb double save from Bowman and Elliott Frear while Samson denied Fisher twice in the space of 60 seconds. And all this before half-time.
The second period was not quite so full of incident but, given the defensive deficiencies on display, goals were still always likely.
Greg Tansey’s incisive pass released Fisher and, when Samson strayed too far from his line, the striker restored parity with a sumptuous chip from 20 yards.
The one thing missing from this pulsating encounter was controversy but that duly arrived when the home side regained the lead.
McDonald, less than a yard out, ought to have buried Elliott Frear’s cross but his header struck the inside of the post before being clawed away by Fon-Williams. Then, to the astonishment of the Thistle players, Mr McGeachie signalled that the ball had crossed the line.
Fortunately, there was no dubiety about Motherwell’s fourth. McDonald turned provider with a perfectly-weighted cross and 18-year-old midfielder Allan Campbell timed his run perfectly to find the net with a downward header.
There is no wriggle room left for Inverness. They look doomed.