Alexander Zverev has served a tournament-leading 80 aces so far at this year's Australian Open.

The German hasn't added to that tally yet today, but he's still started superbly on serve.

That's back-to-back efficient love holds for the third seed.

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The tweaks Carlos Alcaraz has made to his serve, once considered the weaker aspect of his game, has been a hot topic since the start of the year, with many drawing comparisons between his new service motion and that of men's record 24-time major winner Novak Djokovic.

After two aces in his first game, he's forced to grind out a couple of points here - but a big first serve on game points does the trick.

Clinical serving so far from Alexander Zverev, who wraps up a hold to love in less than two minutes with an accurate forehand.

Carlos Alcaraz begins service duties with an ace before racing into a 40-0 lead in an assured start, but a couple of loose forehands keep Alexander Zverev interested.

No bother, though. Have another ace, he says.

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Alexander Zverev is serving first in the opening set - and he's quick to take charge with a booming first serve followed up by a volley at the net to reach game points.

Alcaraz is allowed to 40-30 as Zverev knocks a backhand wide, but misses on the next point to let Zverev escape. Solid enough start for the third seed.

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Spanish world number one Carlos Alcaraz plays German third seed Alexander Zverev in Friday's first semi-final, followed by Italian second seed Jannik Sinner facing Serb fourth seed Novak Djokovic.

It is only the fifth time in the Open era - and the first occasion since 2013 - that the top four men's seeds have contested the semi-finals.

Alcaraz had never gone past the Melbourne quarter-finals before this year, but the 22-year-old looks well placed to win the title and become the youngest man to complete the career Grand Slam.

Zverev, who has lost all three of his Grand Slam finals, has often been accused of being too passive in the biggest matches - but he has proved an awkward match-up for Alcaraz, with the pair evenly splitting their 12 previous meetings.

The roof above Rod Laver Arena is drawn open after the players walk out on to a darkened court, revealing bright sunshine and exposing the crowd to the near-30C heat in Melbourne today. Toasty enough.

Not long to wait until our first men's singles semi-final now!

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Image source, Getty Images

Carlos Alcaraz and Jannik Sinner might have contested the past three Grand Slam title matches together, but they want to lift the Australian Open title for different reasons this year.

Alcaraz is attempting to complete a career Grand Slam, while Sinner is trying to defend his two-time defending champion status.

Now only Novak Djokovic and Alexander Zverev can prevent the duo from meeting in the Melbourne final for the first time.

• Read BBC Sport's semi-final preview here

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Aryna Sabalenka and Elena Rybakina secured their spots in the women's final on Thursday, after progressing through their semi-finals in straight sets.

Two-time Australian Open champion Sabalenka thrashed Elina Svitolina 6-2 6-3, while former Wimbledon champion Rybakina beat Jessica Pegula 6-3 7-6 (9-7).

Elsewhere, Great Britain's Neal Skupski and new American partner Christian Harrison sealed their spot in the men's doubles final by beating third seeds Marcel Granollers and Horacio Zeballos.

Alfie Hewett reached the men's wheelchair singles semi-finals by beating doubles partner Gordon Reid 6-2 6-3, but the pair lost their doubles semi-final.

In the quad doubles, Great Britain's Andy Lapthorne and Australia's Heath Davidson came through their semi-final on a match tie-break and will face top seeds Guy Sasson and Niels Vink in today's final.

We have two blockbuster semi-final matches coming up today, with all of the top four seeds still in contention for the Australian Open title.

But who will reach Sunday's final?

• Carlos Alcaraz (1) v Alexander Zverev (3)
• Novak Djokovic (4) v Jannik Sinner (2)

Will Alcaraz go one step closer to completing a career Grand Slam? Will Zverev continue his bid for a first major title? Will Djokovic stay in the mix for a 25th Grand Slam? Will Sinner's title defence go on?

All of those questions will be answered in due course.

It's day 13 at the 2026 Australian Open.

Today, it's the turn of the men to battle it out for a place in Sunday's final.

Carlos Alcaraz. Jannik Sinner. Alexander Zverev. Novak Djokovic.

The top four seeds remain in contention. Grab the popcorn, folks - this is going to be good...

Image source, Getty Images

Image source, Getty Images

Image source, Getty Images

Image source, Getty Images