Alexander Zverev needed all his power and poise to halt the best Grand Slam run of Learner Tien’s young career. In a tense, heat-affected quarterfinal under the closed Rod Laver Arena roof, the world No. 3 held firm to win 6-3, 6-7(5), 6-1, 7-6(3) and book a return to the Australian Open semifinals. It is his third straight last-four in Melbourne and the 10th major semifinal of his career.

Twenty-year-old Tien walked in with momentum and belief. He had just taken out Daniil Medvedev in a statement win and came to play from the first ball. But on this day, Zverev’s serve was the biggest weapon on the court. He blasted 24 aces and made only one double fault, a clean, steady base that carried him through two tight tiebreak sets and a dominant third set.

Heat, a closed roof, and a fast start

Melbourne turned up the temperature, and tournament officials closed the roof to protect players. Indoors, the conditions played quick. Zverev jumped out with a composed first set, 6-3, leaning on a high first-serve percentage (72% on the day) to control his service games and apply early pressure on return.

Tien, however, refused to fade. The American, coached by former Roland Garros champion Michael Chang, settled into the rallies and found rhythm off both wings. He clawed his way into a second-set tiebreak and edged it 7-5, a hint that this one would not go in straight sets.

“That was a serving clinic under pressure — 24 aces and calm in two breakers.”

Tien bites back, Zverev resets

Good players answer. Great ones reset fast. Zverev came out after the lost tiebreak with a sharper return position and heavier depth, ripping through the third set 6-1. He was ruthless in the sport’s most common patterns: points of four shots or fewer. In those short exchanges, Zverev led an eye-popping 106–68, a clear sign that his first strike tennis—serve plus forehand, return plus backhand—was winning the day.

The fourth set brought the pressure back. Tien’s fearless baseline game kept forcing long, tense games. Zverev praised that quality outright: “Learner from the baseline was playing unbelievable. I don’t think I’ve played anyone who plays that well from the baseline for a very long time.” When the tiebreak arrived, the German’s serve and nerve held, 7-3.

“If Zverev needs 20-plus aces to get through, Tien is already top-tier dangerous.”

The serve that saved the day

From the numbers, the story is simple: when Zverev’s first serve landed, the points mostly went his way. He hit that first ball at a 72% clip and backed it up with 24 aces. Importantly, he kept errors off the serve to a minimum, finishing with just one double fault across four sets.

Tien’s serve had bite too—11 aces—and it set up plenty of baseline exchanges where he often held the edge in rhythm. But the cost was nine double faults, and on indoor days like this one, a few of those at the wrong time can flip a set. As pressure rose, Zverev’s ability to find a spot, especially out wide in the deuce court, stopped runs before they started.

Even Zverev pointed to the serve as the difference, while tipping his hat to the coaching of Michael Chang: “I don’t know what Michael Chang has done with him in the offseason, but it’s incredible. Without my 20 something aces, I probably would not have won today.”

Key stats that defined the quarterfinal

• Aces: Zverev 24, Tien 11
• Double faults: Zverev 1, Tien 9
• First-serve percentage: Zverev 72% (96/133), Tien 63% (82/130)
• Short-rally points (0–4 shots): Zverev 106, Tien 68
• Break points: Zverev saved 100% (3/3); Tien converted 57% (4/7)

Look at the shape of those numbers and you see a clear template: win the first two shots, protect serve, and keep the pressure steady. Zverev did that in three of the four sets. Tien made his push in the two tiebreaks, stealing one and forcing the other, but the German’s margins on serve stayed just a bit higher when it mattered most.

Learner Tien’s fearless rise isn’t over

This was Tien’s first Grand Slam quarterfinal, a milestone week that included a headline win over Daniil Medvedev. At 20, he has the foot speed, the timing, and a brave baseline game that already troubles the very best. Zverev’s praise was not polite — it was earned.

What will stick for Tien? The belief that he can take a set, or two, from top-3 players on the biggest courts in the sport. The film will also show clear growth targets: cut down the double faults, and nudge that first-serve percentage closer to 65–70% in big moments. Do that, and his next second-week trip at a major may last even longer.

“Tien didn’t blink; Zverev just had the last punch. That’s big-time tennis.”

What it means for Zverev and the semifinal picture

Ranked No. 3 in the PIF ATP Rankings, Zverev is back in a familiar spot in Melbourne: the final four. This marks his third straight Australian Open semifinal and his 10th at the Grand Slams. He reached a major final last year in Melbourne and is still chasing his first Grand Slam title, a prize that has narrowly eluded him.

Context matters here too. Zverev finished the 2025 season at No. 3 after winning just one title in Munich. That stat cuts two ways: his baseline level is high and steady, but to lift a Slam, he may need more first-strike aggression like we saw today, especially in the tiebreaks. The serve, clearly, is the foundation.

He now awaits the winner of the evening showdown between world No. 1 Carlos Alcaraz and home favorite Alex de Minaur, a match that will decide his semifinal opponent. Against either player, Zverev’s pathway is the same: protect serve, lean into the short exchanges, and keep returns deep to draw mid-court balls. If the roof closes again, those first-strike patterns become even more valuable.

Final word

This quarterfinal had all the marks of second-week Slam tennis: heat, swings of momentum, and thin margins decided by a handful of big serves. Zverev found them, often, and at the right times. Tien earned respect and a crowd of new fans. One moves on, one learns and reloads.

For Zverev, two more matches stand between him and a long-awaited first major. If his serve holds this level, he will like his chances against anyone left in the draw. For Tien, the message is simple: this level belongs to him now. The next step is making it routine.