MADRID (AP) — Andy Murray’s struggles continued with a 6-3, 6-3 loss to lucky loser Borna Coric in the third round of the Madrid Open on Thursday, while defending champion Novak Djokovic and four-time champion Rafael Nadal made it to the quarterfinals.

Djokovic defeated Spanish veteran Feliciano Lopez 6-4, 7-5, while Nadal eased past Nick Kyrgios of Australia 6-3, 6-1.

The top-ranked Murray was outplayed by the 20-year-old Croatian to lose his fifth match of the year.

Murray has won only one tournament this season and hasn’t made it past the semifinals in the three clay-court tournaments he has played.

“Most things weren’t working particularly well,” Murray said. “I started the match OK, but when I started to go behind I didn’t find any way to improve my game or to make it more difficult for him. I just kind of let the same things keep happening, making mistakes very early in a lot of the rallies. I wasn’t building any points really.”

The 59th-ranked Coric became the first lucky loser to reach the quarterfinals in Madrid. He only made it to the main draw after Richard Gasquet withdrew because of a back injury.

“It’s a huge win, for sure. It’s going to mean to me a lot,” Coric said. “Obviously he didn’t play very good today. That was very obvious. I have noticed it from the beginning.”

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Coric will try to win his second tournament this season. He won his first career title in Marrakech, Morocco, last month.

He will play the quarterfinal against Dominic Thiem of Austria, who won a thriller against Grigor Dimitrov of Bulgaria 4-6, 6-4, 7-6 (9).

Murray, who lost last year’s final to Djokovic in Madrid, had 28 unforced errors in a disappointing outing under the closed roof of the center court in Madrid. He was broken three consecutive times in the first set, and once in the second to give Coric a 5-3 lead that he converted to close out the match.

Murray won his only title of the year in Dubai and had started the clay season trying to regain his form following a right elbow injury that kept him out of the Miami Open and the Davis Cup quarterfinals. He lost to Albert Ramos-Vinolas in the third round in Monte Carlo after blowing a 4-0 lead in the deciding set, then was eliminated by Thiem in the semifinals of the Barcelona Open.

Second-ranked Djokovic has also struggled this season but stayed alive in Madrid with the two-set victory over Lopez.

The Serbian player was in control during his service games and broke Lopez once in each set to secure the victory. Djokovic saved the only break point he conceded to Lopez, who was playing in the tournament for a record 16th time.

“The level was definitely very high today I thought from both players,” Djokovic said. “I think Feliciano played really well, especially in the second set. I wasn’t winning too many points on his service games until the…