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.
"I think if he continues playing as he's been playing today and winning matches, it'slogical we're going to see the same Djokovic as we're used to seeing". I wasn't expecting myself to play well this week at all. "Eventually the game will come together".
Nadal finally broke in the third game of the second set before having to stave off four break points on his own serve to consolidate his lead at 3-1.
However, a mixture of Almagro nerves and Djokovic upping his intensity saw the world No. 2 react immediately to level at 3-3.
Dimitrov worked two more match-points, both thwarted, and Thiem played some big-time winners to earn two match points of his own, earning the last with a backhand volley victor, and he drew one last error from Dimitrov for victory, 7-6 (9).
A finalist in Madrid in 2014, Nishikori lost his last 10 matches against Djokovic, including in the semifinals in Madrid past year.
After a near-flawless serving display, Lopez watch a bullet return speed past him to fall into a triple-match point hole.
Tennis - ATP 1000 Masters - Madrid Open - Men's Singles Quarterfinal David Goffin of Belgium v Rafael Nadal of Spain - Madrid, Spain - 12/5/17 - Nadal celebrates at the end of match.
Kyrgios and Nadal have only met twice with the Australian making his breakthrough with a four-set win over the 14-time Grand Slam champion at Wimbledon in 2014.More news: Learjet crash near New York City kills 2 crew members
The Australian defeated Marcos Baghdatis in the first round Ryan Harrison in the next, both in straight sets, but he faces a completely different test against Nadal.
David Goffin awaits the victor of Nadal's clash with Australian Kyrgios as the Belgian beat world number six Milos Raonic 6-4, 6-2.
Kei Nishikori recovered from a awful start to beat Argentine Diego Schwartzman 1-6, 6-0, 6-4.
Djokovic, the defending champion, advanced when Kei Nishikori withdrew before their quarterfinal because of a wrist injury. Djokovic won 6-1, 4-6 and 7-5.
In the WTA Madrid Open, Svetlana Kuznetsova remained one of only three of the top 10 seeds left in the draw with a 6-4, 7-5 win over Wang Qiang to reach the quarter-finals.
The third-seeded Halep, who also lost the 2014 final to Maria Sharapova, will play to keep her title against eighth-seeded Svetlana Kuznetsova of Russian Federation or Kristina Mladenovic of France. 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.
"Even though I played really badly, my attitude has been very positive", Nadal said.
"I'm still finding my way to that consistency level and quality of tennis that I'm looking for", said Djokovic.
"I haven't had the best preparations coming into this tournament. I was enjoying very much". This match also serves as a great prelude to the French Open.