Retiring tennis superstar Rafael Nadal said his Davis Cup quarter-finals singles defeat by Dutchman Botic van de Zandschulp on Tuesday was "probably my last match".

The 22-time Grand Slam winner will call time on his glittering career at the end of Spain's participation in the tournament in Malaga this week.

Nadal lost 6-4, 6-4 against the world number 80, leaving Spain's Davis Cup hopes hanging by a thread.

"If I was the captain I would change me probably (if Spain reach the semi-finals), but at the end of the day it's not my decision," Nadal told reporters.

"And I'm sure (the captain) will make the best decision possible for the team... probably that was my last match...

"I lost my first match at the Davis Cup, and I lost my last one, so we close the circle."

Nadal's involvement in the tie was not certain, with his career ravaged by injuries in recent years, but captain David Ferrer called on the 38-year-old to open the finals for Spain before an adoring home crowd.

"At the end of the day he has to make decisions and he made the decision thinking what's the best for the team and not for myself, I respect that," said Nadal.

"We went on court, we lived that moment, trying to do my best, trying to stay as positive as possible, positive energy, it was not enough.

"Hats off to Botic, he was better than me, now it's not necessary to analyse the match any more."

Nadal appeared emotional during the Spanish national anthem before the match.

"I was having an emotional day, nerves before what could be my last singles match as a professional," added Nadal.

"The emotions hearing the national anthem for the last time as a professional were very special, mixed feelings makes things a little bit more difficult."

World number three Carlos Alcaraz faces the Netherlands' Tallon Griekspoor in the second singles rubber to try and keep Spain's Davis Cup dream alive and prolong Nadal's farewell.