MELBOURNE, Australia (AP) After snuffing out local hopes for yet another Australian Open, Grigor Dimitrov huddled with Nick Kyrgios at the net and the pair exchanged encouraging words.
It was Kyrgios, having just lost 7-6 (3), 7-6 (4), 4-6, 7-6 (4) in the fourth round in a typically tempestuous performance, who left No. 3-ranked Dimitrov with this message: ''Believe.''
Dimitrov has never won a major, coming closest here last year before losing a semifinal to Rafael Nadal in five sets, but is enhancing his credentials as a next generation champion.
Nadal secured his spot in a 10th Australian Open quarterfinal earlier Sunday on Rod Laver Arena, beating Diego Schwartzman 6-3, 6-7 (4), 6-3, 6-3 in 3 hours and 51 minutes.
The 16-time major winner draped an arm around his Argentine friend and patted him on top of the head. If he needed a fitness test in the first week in his comeback from an injured right knee, he got it.
''A great battle ... he's a good friend of mine,'' Nadal said. ''This is the first big match that I played in 2018. That's confidence for myself ... confidence I can resist for four hours on court at a good intensity.''
Nadal will next play 2014 U.S. Open champion Marin Cilic, who collected his 100th Grand Slam match win with a 6-7 (2), 6-3, 7-6 (0), 7-6 (3) victory over No. 10 Pablo Carreno Busta.
''I had the 300th win of my career at the U.S. Open in 2014, so this is also beautiful one,'' Cilic said of his latest major milestone. ''I hope I'm going to continue and gather three more here.''
Nadal lost last year's Australian Open final to Roger Federer, but went on to regain the No. 1 ranking and win the French and U.S. Open titles before bringing his season to a premature end because of an injured right knee.
Despite not playing any competitive matches in his Aussie Open preparation, Nadal advanced through three rounds without dropping a set.
That streak finished when Schwartzman took the second set, rebounding three times after dropping serve to break back and win the tiebreaker.
Nadal lifted to win the third, but Schwartzman didn't relent.
The second game of the fourth set lasted almost 13 minutes, with Nadal finally holding after saving five break points.
He broke again in the next game to regain control.
''It was a good test for me. It was a lot of hours on court. Moments under pressure,'' Nadal said.
Britain's Kyle Edmund reached his first Grand Slam quarterfinal with a 6-7 (4), 7-5, 6-2, 6-3 afternoon win over Andreas Seppi and could relax and watch the night-time entertainment featuring Dimitrov and Kyrgios. They all played two weeks ago in Brisbane, where Edmund lost to Dimitrov, who lost to eventual champion Kyrgios.
Both Dimitrov and Kyrgios got tense at key times in the night match. Dimitrov was broken while serving for the match. Kyrgios was called for a foot fault, double-faulted on a set point and smashed an easy overhead into the net on a break point after dominating the rally. He had 36 aces, and some second serves recorded at faster than 202 kph (125 mph).
''Only a couple points in it, you know. It wasn't like I got demolished out there,'' said Kyrgios, who missed the chance to end the drought for local men that dates back to the 1976 Australian Open. ''I had a lot of chances to win the match and I just came up short.''
He tipped his mate Dimitrov to go far.
''He hasn't even found his best form yet and he's still getting through all those matches, which is pretty frightening,'' Kyrgios said. ''Once he finds his feet and he has more confidence, he's got a real chance at winning it.''
Dimitrov thanked him for the support, and said he's growing more confident in his game.
Caroline Wozniacki continued to cash in on her second chance, reaching the quarterfinals here for the first time since 2012 with a 6-3, 6-0 win over Magdalena Rybarikova.
After saving match points and coming back from 5-1 down in the third set of her second-round win, No. 2-ranked Wozniacki said she was ''playing with the house money'' and had nothing to lose.
Wozniacki next plays Carla Suarez Navarro, who rallied from a set and 4-1 down to beat No. 32 Anett Kontaveit 4-6, 6-4, 8-6.
The other quarterfinal will feature the winners of two tune-up events. Brisbane International champion Elina Svitolina beat Denisa Allertova 6-3, 6-0 in a match that started just before midnight.
Fourth-seeded Svitolina next plays Hobart International winner Elise Mertens, who beat Petra Martic to reach the quarterfinals in her Australian Open debut.
More AP coverage: www.apnews.com/tag/AustralianOpen