Scotland dropped to third in their European Under-21 Championship qualifying group after Dimitrios Nikolaou's last-minute penalty gave 10-man Greece a 1-0 victory at Tynecastle.
The hosts looked to have gained the advantage when Panagiotis Retsos was sent off after the break.
But when Daniel Harvie handled the ball in the box late on, Nikolaou converted the penalty for the victory.
The result moves Greece into first place, two points above Scotland.
Scot Gemmill's side host Croatia in their next match on 27 March.
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Greece snatch dramatic winner
Scotland knew that a victory against Greece would take them clear in Group 4 and Gemmill's side came close to an early opener.
The impressive Billy Gilmour combined with Jordan Holsgrove to set up captain Allan Campbell, only for the Motherwell midfielder's strike to fall just the wrong side of the Greek goal.
Just before the half-hour mark Gilmour came close when his shot from 22 yards went narrowly over.
The visitors were much better after the break and Ross Doohan in the Scotland goal was at full stretch to push away an effort by striker Argyris Kampetsis.
However, just after the hour mark the visitors were reduced to 10 men when Retsos was shown his second yellow after a cynical challenge on Gilmour.
Gemmill introduced Glenn Middleton into the match and Greece goalkeeper Marios Siampanis had to be on his toes to keep out a cross from the winger which looked to be creeping under the crossbar.
And just as it looked as if the Scots would record their third 0-0 draw in the group, the visitors snatched a dramatic winner in stoppage time.
Full-back Harvie needlessly handled inside the box and centre-half Nikolaou smashed the ball home to put Greece top of the table in the race for the finals in Hungary and Slovenia in two years' time.
'Lots to be positive about' - reaction
Scotland head coach Scot Gemmill: "We have to take the positives. We really did well in the first half, we had 60% possession and were controlling the game, containing a very good team.
"Then the game swung in the second half. We needed to do better against 10 men, but overall there's a lot for the players to be positive about. We're halfway and have had some really good performances so there's a lot to play for."