The NBA was just shown a prime example of why preseason basketball matters. San Antonio lost to the Mavs 109-120. Everyone who played significant minutes during the exhibition seemed comfortable.

Spurs fans knew Victor Wembanyama would be rusty in the season opener. He played in two preseason games, playing only 17 minutes in one and 23 minutes in the other. But that didn't make the performance any easier to watch.

The reason lies in the juxtaposition of the unbridled excitement before the first game of the year and the disappointing performance of your star player afterwards.

In 28 minutes, Wemby shot 5/18 from the field and 1/8 from three for 17 points. He shot 6/6 from the free throw line – an encouraging sign – and added nine rebounds, one assist and one block. His annoying problem with losing the ball became apparent early on with four turnovers in the first half. However, he managed to finish the game and score the same four points.

There's no worry that Wembanyama won't shake off the rust and start looking like the franchise player that Spurs fans have grown to love, but this game was a poor performance. However, the poor shooting was somewhat expected, so the disappointment goes beyond the numbers.

From the start of the game, the Mavericks were the more physical team. This has little to do with the strength of the players, which is important since Dallas is the older team with players with fully developed bodies. It is a matter of effort and determination.

As much good as Wemby brings, he's not perfect and tonight he wasn't as demonstrative as he needed to be. Losing the ball around the rim with minimal contact on offense and allowing the opponent to take the ball away from him on rebounds is not what you expect from a 7'4″ alien.

The bigs for Dallas are strong, but Wembanyama's length should negate much of that. He needs to work on strengthening his hands to confidently catch passes and rebounds. The ball should be safe in his hands as soon as he touches it. At the moment he is fumbling the ball too much, which is affecting his ability to make quick movements.

If he has to think too much about securing the ball, it slows him down and forces him to think more than act on his instincts. We've seen several instances of hesitation from Wemby, and while some of it is simply down to rust, it's also partly down to him not catching passes cleanly. He struggled with this issue last season and it needs to be addressed quickly.

The next game is Saturday against the Houston Rockets, where Wemby will look to shake off any more rust. He needs to be a stronger presence against Alperen Sengun, and coach Popovich will probably tell him that. That will be a grade for another day – he earned the grade he got for the first game.