Here are some scattered thoughts on the Australian Open as it reaches the semi-final stage.

1. Rafa Nadal’s knee problems have exacted a tremendous physical toll, but I’m more worried about its psychological impact. The boundless enthusiasm of the old Nadal has disappeared, replaced by a weary feeling that he’s working a job. Tennis has enough dour personalities — Andy Murray, I’m looking at you. It would be a shame if Nadal joined their ranks.

2. Anyone who is a tennis fan can’t help but be delighted by the globalisation of the sport. As Australia and the US have faded (not a single male slam winner since 2003 and only the Williams sisters in the women’s side), non-traditional tennis countries like Serbia have stepped out. The semis at the Australian Open have a Croat and two Chinese players.

3. Roger Federer has had a schizophrenic tournament but Hyde has kept Jekyll at bay so far. He’s had periods of shocking play against Andreev and Davydenko. Even an inconsistent Federer should be able to take out Tsonga but that won’t cut it in the likely final against Andy Murray on Sunday.

4. First Kim Clijsters, now Justine Henin. Any grand slam winner from the past two years needs an asterisk against their name. Their un-retirements have given the women’s game new life and once again made it the equal of the men’s game.

5. Major props to Fabrice Santro, who made up for his five-foot-nothing height to became the most inventive tennis player around. He has now played slams in four different decades.