It was the 23rd straight win for Nadal since 2005, setting the Davis Cup record combining singles and doubles.
Rafael Nadal returned to action after a long injury layoff on Friday, comfortably defeating Philipp Kohlschreiber 6-2, 6-2, 6-3 to leave Spain even with Germany in the Davis Cup quarterfinals.
It was the 23rd straight win for Nadal since 2005, setting the Davis Cup record combining singles and doubles.
The top-ranked Nadal hadn't played since the Australian Open quarterfinals because of a right hip injury, and was never challenged by the 34th-ranked Kohlschreiber at the bullring staging the clay-court tie in Valencia.
"It's positive, winning in straight sets. I feel comfortable back on the clay," Nadal said.
"To play at home at a bullring stadium, it's very unique. Coming back from injuries is always difficult, but it's great to be in front of my crowd on a very memorable day."
Germany won the opening singles when world No. 4 Alexander Zverev defeated David Ferrer 6-4, 6-2, 6-2.
Nadal, in his first Davis Cup tie since 2016, had 30 winners against only eight by Kohlschreiber, but the Spaniard finished with eight double faults. Nadal had 18 break opportunities, converting seven.
Earlier, Zverev cruised past the 33rd-ranked Ferrer with four aces and 27 winners.
"I played more aggressively as the match went on. It's my first clay-court match in a very long time, so it was great to find my rhythm so quickly," Zverev said. "With Nadal in their team, it's a point we're not expecting to get, so it's important to start well."
This is the teams' first Davis Cup meeting since 2004.
Spain is trying to extend its winning streak at home to 27 ties. Italy holds the Davis Cup record with a 29-tie unbeaten run at home from 1949-64. Spain hasn't lost a tie as host since the first round in 1999 against Brazil.
