Inverness beat Dunfermline to all but seal the First Division title as only a huge turnaround in goal difference will deny the Highlanders promotion.
Caley Thistle have a better goal difference by 18 and have also scored more goals than Dundee, who can now only equal the leaders' points tally.
Adam Rooney struck his 25th goal of the season early in the second half to give Inverness a vital advantage.
And fellow Dubliner Richie Foran added a second on 62 minutes to seal the win.
Terry Butcher's side are now set for an immediate return to the Scottish Premier League, from which they were relegated 11 months ago.
It was the Pars who were first with the ball in the net - twice in the first 26 minutes - but both were chalked off.
Steven MacDougall's effort was disallowed after he was adjudged to have been marginally offside and Nick Phinn was yellow carded for a deliberate hand ball as he controlled his net-bound effort.
Caley Thistle had much of the possession and looked dangerous on the break but created little in a first half that ended with Andy Dowie scooping a tempting Willie Gibson free-kick hight and wide.
Perhaps encouraged during the interval by news that other results were going their way, Inverness emerged like a whirlwind in the second half and came within a hairsbreadth of bundling the ball over the line, both with Ross Tokely's original effort and Nauris Bulvitis' follow up from a Jonny Hayes corner.
The vital breakthrough came on 55 minutes, when Tokely sent a long high ball forward for Rooney to lob it home from 20 yards.
And seven minutes later, Foran struck home from a tight angle on the left.
Dunfermline were by no means out of it and kept home goalkeeper Ryan Esson well employed, especially with a sizzling effort from Gary Mason.
The euphoric atmosphere among the home fans who were looking to wrap up the title on the day subsided slightly as news arrived of Dundee battling back for a 2-2 with Morton, theoretically keeping the Dens Park side in the chase.
Inverness, who were at one point seventh in the table and 13 points off the lead, are now 19 games unbeaten and can confirm a title triumph by avoiding defeat against Ayr United next weekend.
Inverness manager Terry Butcher: "We're not there yet, even though we have a better goal difference by 18 and I see it going to Saturday down at Ayr, but it's something to look forward to.
"The boys have worked really hard with seven successive wins, a 19-match unbeaten run. If you had said that a few months ago, no-one would have believed you.
"I don't know what the odds would have been - you would have got astronomical odds.
"The whole squad has been magnificent. There were gaps in the squad before because it was new and people didn't know each other.
"But, the more the season has worn on, the more that unity has grown and grown. There's a unity and a respect for each other, which wasn't there at the start of the season, and everybody has played their part."
Inverness CT: Esson, Proctor, Tokely, Bulvitis, Golabek, McBain, Hayes (Sanchez 72), Duncan, Foran (Djebi-Zadi 90), Rooney, Odhiambo (Eagle 87). Subs Not Used: Allison, Stratford.
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