Novak Djokovic vs Jannik Sinner Australian Open 2026 semifinal: One number that could give the Serb an edge

Second serve factor

The minuscule edge is simple reading: Djokovic wins a shade more than half the second serves he returns, Sinner wins a shade more than half the second serves he plays in. But the slight edge could have an outsized impact on their semifinal on Friday if the Italian doesn’t get his serves right on Friday.

PREVIEW | Novak Djokovic vs Jannik Sinner: Serbian legend will have to make his own luck in Australian Open semifinal

Sinner’s serve is not a weakness; its reliability has often been a strength. But he has shown slight tentativeness in making first serves over the past few months; his first-serve success rate stands at 65.4% in the tournament. That is average but nothing to write home about.

And when he does continually miss it and has to throw in second serves, they are often safe and predictable enough for opponents to latch onto them and make him pay. It’s not a mere coincidence that in the only match in which he visibly struggled in Melbourne this week, due to heat and cramping and a spirited opponent in American Eliot Spizziri in a four-setter in the third round, he won just 43% of the points behind his second serve. In last year’s US Open final, which he lost in four sets to Carlos Alcaraz, he won only 48% of the points behind his second serve.

Age and a weakened physicality may have led to a slight drop off in other parts of his game, but Djokovic still remains a razor-sharp returner. He will be ready to take advantage of any lapses in that area of Sinner’s usually consistent and high-level game.