Great Britain were beaten 3-1 by Spain in their Davis Cup tie after Cameron Norrie lost in four sets to world number 21 Albert Ramos-Vinolas.
It was another superb effort from Norrie, ranked 114, but he finally lost 7-6 (7-4) 2-6 7-6 (7-4) 6-2 in three hours and 43 minutes in Marbella.
Kyle Edmund could have played in a deciding fifth rubber had Norrie won.
Britain now face a play-off in September which they need to win to stay in the World Group in 2019.
Norrie, 22, had come back from two sets down on Friday to defeat world number 23 Roberto Bautista Agut.
- Norrie debut ‘one of the most impressive of all time’
- Germany beat Australia in Davis Cup
- Live scores, schedule and results
“I can’t speak highly enough of what Cam has done all weekend,” Great Britain captain Leon Smith said.
“People might have thought Friday was a one-off but he did it again against another high-quality player. He pushed him really close and I’m really proud of him.
“The only way is up for him.”
The first and third sets lasted 75 minutes and 76 minutes respectively with Norrie’s standard and energy levels finally dropping after he lost his second tie-break.
Ramos-Vinolas, who beat Liam Broady in the opening match of the tie on Friday, lost only two points on serve in the fourth set as he took Spain into April’s quarter-finals where they will face Germany.
Norrie impresses again but can’t keep the tie alive
While heavy favourites Spain ultimately prevailed, Norrie was the revelation of the weekend as he pushed two world-class clay-courters to the limit despite his inexperience.
He played his first professional match on red clay on Friday, and these Davis Cup matches were the first occasions he had gone beyond three sets.
The Briton was quickly 4-0 down and faced two set points at 5-2 on Ramos Vinolas’ serve but somehow dragged himself to a tie-break in an incredible first set featuring eight breaks of serve.
A sensational pass from wide of the tramlines in the tie-break typified Norrie’s tenacity and inspiration but two errant forehands then cost him as Ramos-Vinolas closed out the first set.
The Briton would not go away, holding from 0-30 down in his opening two service games of the second set, and winning five games in a row to level the match.
Norrie then fell 3-0 down in the third set but twice came back from a break down to force a second tie-break. Again, though, it was Ramos-Vinolas who took it with three Norrie errors in a row from 4-4 handing the Spaniard the set.
As well as Norrie played, he was never in front in the match and the effort of coming from behind finally told in the fourth set.
GB fight odds without Murray and Edmund
A British win in the tie was always very unlikely with Andy Murray recovering from a hip operation and Australian Open semi-finalist Edmund not included in Friday’s opening singles rubbers because of his own hip problem.
Spain were without world number one Rafael Nadal, but the five players in their squad are ranked in the top 40 and they have now won 28 of their past 29 Davis Cup ties on clay. Norrie and world number 165 Broady were both making their debuts in the competition.
Norrie’s superb comeback win against Bautista Agut gave Britain hope of a huge upset but defeat in Saturday’s doubles for Jamie Murray and Dominic Inglot meant they had to win both singles on Sunday.
Edmund practised on the Puente Romano court on Saturday evening to test his fitness but Smith would not have been able to select Norrie on Sunday if he had put the world number 26 out first. Norrie played in the second singles on Friday so could only be chosen for the first match on the final day.
Smith will now hope to have a fit Andy Murray alongside Edmund for September’s play-off but at least knows he has another strong singles option in Norrie.
‘One of the most impressive debuts of all time’ – analysis
1977 Australian Open finalist John Lloyd on BBC Two
It was a tremendous match. Cameron Norrie, what a performance. To go against world-class players, with no experience, and to embrace this occasion like he has is quite extraordinary.
We’ve got another player coming up now who is going to be tremendous. What a back-up. He loves the big occasion. There is no bigger occasion than what he’s just played in – a Davis Cup match, to make his debut and go out there, not be timid, go for it.
This match was close. It could have gone either way. It’s a staggering performance and one of the most impressive debuts of all time.