Evans has lost all four Davis Cup matches he has played in
Great Britain fell to an embarrassing Davis Cup defeat after Dan Evans lost in five sets in the decisive singles match to hand Lithuania a 3-2 victory.
The 6-7 7-5 6-0 2-6 6-4 win for Laurynas Grigelis means Britain must now beat Turkey, who lost to Ireland, in a relegation play-off in July.
The loser of that tie will drop into Europe/Africa Zone Group III - the lowest tier of the competition.
James Ward's loss to Ricardas Berankis meant the final rubber was decisive.
GB have faced a Europe/Africa Group II play-off before - in 1995 when they beat Monaco 5-0 - but given the Lawn Tennis Association's annual £40m-plus budget, Sunday's defeat will raise questions about the future of team captain John Lloyd as well as chief executive Roger Draper.
Britain began the day 2-1 up but they must now face up to the embarrassment of coming unstuck against a country with only three world-ranked singles players and a team made up entirely of teenagers.
Evans's defeat was his fourth in two Davis Cup appearances and comes against a player ranked 269 places below him at 521 in the world and who has never played a match on the ATP World Tour.
The pair seemed well matched in the early stages, and the first set went with serve the whole way through to a tie-break.
Evans led 4-2 at one point before being distracted by two disputed line calls, and in the face of an extremely vociferous home crowd, whose behaviour clearly upset Lloyd.
But when Grigelis put a return long, the set was Great Britain's - taking the edge off the crowd.
Evans survived a wobble in the ninth game of the second set but had no such luck on his next service game, where Grigelis clinched the first break of the match to go 6-5 up, and that was the start of a dramatic slump for Evans.
His opponent was in inspired form and seemed incapable of hitting anything other than winners as he won eight games in a row to edge the second set and romp to the third 6-0.
The end of the third was a blessed relief for Evans, who promptly rediscovered his form in a bizarre fourth set.
Evans secured his first break of the match to go 2-0 up, lost the next two and then won four on the bounce, clinching the set 6-2 courtesy of a Grigelis double-fault.
With the outcome of the entire tie dependent on the final set of the final match, it was always going to be a war of nerves, and it was Evans who succumbed first, as he was broken in the fifth game.
To the delight of a hugely excited home crowd, Grigelis backed it up by holding his own serve to go 4-2 up, and from that point onwards, his momentum was irresistible.
Evans has now lost all four Davis Cup matches he has played in
The day began in disappointing fashion for Great Britain as Ward lost the opening singles match 7-6 (7-4) 6-3 6-4.
Despite beginning with a double fault, Ward soon found his rhythm hitting several aces early on, but failed to back it up by breaking his opponent.
Eventually it needed a tie-break, won by the Lithuanian, to separate the pair, with the last three points all Ward errors.
Ward began to show nerves in the fourth game of the second set, when he was taken to deuce on his serve for the first time, and two service games later, the pressure got to him.
A forehand shot into the roof followed by another into the net saw Berankis clinch a vital break for 5-3.
That gave him the chance to serve for the second set, and despite going 40-15 up, Ward was hauled back and Berankis clinched the set with an ace.
Game three of the third set provided the best rallies of the match so far, and saw Berankis have a break point, salvaged by Ward with a fine backhand winner.
The Great Britain player had a chance of his first break in the match in game six, but Berankis showed good form from the baseline and the chance was gone when Ward put a forehand return wide.
The full cost of that error was revealed in the next game, when Berankis claimed the break and nudged ahead.
Twice Ward managed to reclaim break points with fine serves, but at the third time Berankis gained the upper hand over his opponent and broke his serve to go 4-3 up.
Berankis then held to move within a game of victory, and although Ward then held to love, it was just a temporary delay as Berankis served for the set and the match, a victory which was sealed when a Ward backhand went into the net.
"It came down to a few points," said Ward, who beat Grigelis on his Davis Cup debut on Friday.
"He served really well today. I served well as well but I could have done a bit more on the return and make him play a few more points. But there was not much in it, just two breaks. It's tough."