"Most things weren't working particularly well".
Most notably, perhaps, Kyrgios beat Nadal at Wimbledon in 2014 as a teenager, though Nadal won their only other match, on Rome's clay last year-though it took three sets and two and three-quarter hours.
The 59th-ranked Coric became the first lucky loser to reach the quarterfinals in Madrid.
Coric, who lost in the second round of qualifying to Mikhail Kukushkin, got into the main draw when Richard Gasquet withdrew.
"It's a huge win, for sure".
"In the end, I played as I had dreamed".
Novak Djokovic says he could have a new coach in place as soon as the French Open in less than a fortnight.
In probably the men's match of the tournament so far, No. 8 seed Dominic Thiem came back from a set down to beat Grigor Dimitrov in a thrilling deciding tie-break.
Predominantly playing the slice, Lopez hit the drop shot effectively at times to drag his opponent forward, but Djokovic drained errors or shot balls from the Spaniard's one-handed backhand as well.
Djokovic was not broken in the 93-minute clash, and faced just one break point. "But I think by the French Open, or after the French Open, I'm going to have someone", he said.
"I wouldn't have been able to play at 100 percent today", Nishikori told a press conference, explaining that his wrist started hurting slightly after Thursday's third-round match against Spanish veteran David Ferrer and the pain had gotten worse Friday morning.
Djokovic hasn't made it this deep into any event since winning the title in Doha at the beginning of the year.
Then previous year, he suffered a six-match losing streak through Madrid, Rome and the French Open and found himself at No40 in the rankings, his lowest since February 2013.
The world number two had coasted through his service games, winning 86% of his points behind his first serve after nine games.
Of course, the younger player tried to impose his strokes, as the only way he could hurt Nadal on this kind of surface, but he just wasn't there to compete on a high level, making way too many easy mistakes and never finding the right rhythm.
David Goffin beat fifth seed Milos Raonic 6-4 6-2 to set up a meeting with the victor of Rafael Nadal and Nick Kyrgios.
At deuce, Lopez sent a forehand that caught the baseline and Djokovic appeared to stop the rally for a closer inspection. "It's always tough to play with someone who has a big serve".
Halep faces Latvian Anastasija Sevastova in yesterday's semi-finals after the world No. 22 saw off Kiki Bertens 6-3, 6-3.
Third-seeded Simona Halep of Romania defeated 16th-seeded Samantha Stosur of Australia 6-4, 4-6, 6-4.