👋 Welcome back to The Daily Theory, our morning rundown to help you stay on top of your favorite sport. I’m Allen McDuffee, your guide to all things tennis.

Today’s issue of The Daily Theory will be slightly abbreviated while the tours recalibrate following the Australian Open. With Davis Cup action later in the week and qualifying rounds still accounting for much of today’s action, there’s a moment to catch our collective tennis breaths. Still, we have a few things to chew on.

Let’s tennis!

Three Points

🎾 Defense, completed: Defending a major is difficult for any player (save for Rafa at Roland-Garros), but especially the first one. Jannik Sinner checked that achievement off his list, taking Alexander Zverev in straight sets at this year’s Australian Open. “Defending the title is always different. You have this extra pressure, but I always enjoy it. Every match has been very tough,” Sinner said after the match.

🎾 Only the heat had a chance of winning: Jannik Sinner dropped only two sets on his way to taking the Australian Open title — both of them during the day when heat was a factor. This data point highlights two things: exactly how dominant Sinner is in the field and that the fitness issues he’s faced in the past aren’t totally resolved.

🎾 Winning, making history: Top seeds Katerina Siniakova and Taylor Townsend won the women’s doubles title, defeating number three seeds Hsieh Su-wei and Jelena Ostapenko in a two-and-a-half-hour thriller, 6-2, 6-7, 6-3. Sinakova has now become one of the most dominant doubles players in decades, winning 10 majors — the first to do it since Martina Hingis captured her tenth at Wimbledon in 2015.