Rafael Nadal survived an early scare at the Barcelona Open on Friday to beat Argentine Juan Ignacio Chela 6-4, 6-2 for a place in the semi-finals.
The top seed, trying to win the title for the fourth successive time, looked off-colour early on to trail 4-2 but roared back to clinch the match.
He will next meet unseeded German Denis Gremelmayr, who edged out another Spaniard, 10th seed Nicolas Almagro 6-2, 3-6, 7-6.
Nadal conceded just four games to the Argentine the last time they met but Chela began superbly, taking risks and putting the top seed under rare pressure.
Chela broke the Nadal serve to love to lead 4-2 but the match effectively hinged on an epic seventh game.
Chela had five chances to extend his lead to 5-2 but Nadal suddenly sprung to life, taking his third break-point chance to get back on terms.
He broke again two games later before serving out the set and after breaking the Argentine in the first game of the second set, he eased to victory.
"If it had gone to 5-2 it would have been very difficult to win the first set," Nadal said in a courtside interview.
"But getting back to 4-3 gave me a lot of confidence and I am very happy to be in the semi-finals for the fourth year in a row."
Second seed David Ferrer came through his second tough battle in as many days to reach the semi-finals, beating Spanish compatriot Tommy Robredo 7-6, 6-4.
The world number five, pushed hard by Ecuadorian Nicolas Lapentti in the previous round, battled past the sixth seed in a match lasting two hours, five minutes.
He will play 14th seed Stanislas Wawrinka for a place in the final after the Swiss fought off the challenge of another Spaniard, Albert Montanes, 6-3, 6-7, 6-4.
Wawrinka held match point in the second-set tiebreak, but the Spanish world number 87 hit back to force a decider.
Montanes then fought back from 5-2 down in the third set to be back on serve at 5-4, only to lose his serve again as the Swiss claimed victory after two hours, 46 minutes.
"I knew I had to be aggressive and go for my shots, because Montanes is a very good claycourt player," Wawrinka said.
"I could have closed it out in the second set but I was not worried because I was confident I could win it in the third set."