Former world No 1 Maria Sharapova has criticised the length of the tennis season after beating Russian compatriot Nadia Petrova to reach the semi-final of the Australian Open.

Sharapova overcame a spirited performance by her opponent to win 7-6 (8/6), 6-4 in a match marked by the copious amount of unforced errors and will play Justine Henin-Hardenne for a place in the final.

However, it was the length of the season that dominated Sharapova's thoughts following the match and she called for it to be shortened to attract more fans.

She said: "Everybody knows that the tennis season is way too long. I mean, it's about ten-and-a-half months of the year. If you tell it to anyone else, they think you're crazy.

"A lot of the times with the scheduling, fans don't know sometimes what tournaments are bigger than the others. There needs to be a better structure on the tour. But, again, that is not something that is going to happen very quickly."

The 18-year-old also criticised the bodies which run the men's and women's tours, saying some officials may be putting business interests ahead of player welfare.

She said: "I also think that this is a big business for everyone.

"The WTA Tour and the ATP and the ITF and everyone that's in this whole tennis world needs to come together because I think each and every one of them is trying to make a business in their own little shell. In order to make this game bigger and better, I definitely think they need to come together."

Her enlightening comments were a contrast to the scrappy nature of the contest.

Petrova, seeded sixth, had broken Sharapova's opening service game but allowed her opponent to break back several times.

Petrova regained the lead with two more important service breaks in the first set but on each occasion Sharapova managed to break back and the set was forced into a tie-break.

Petrova quickly went 6-4 ahead with a serve but it was Sharapova who dug deep to win 8-6 after her opponent double-faulted. The former Wimbledon champion then broke Petrova's service game to start the second set and pulled further in front with another service break to run away with the second set.

However, Sharapova knows she will have to improve when she faces Henin-Hardenne.

"I'll have to step it up, that's for sure," she said.

"But I'm confident that I can. I'm moving a lot better. I feel like the biggest weapon of mine is just my toughness, and I know that over any girls, until the end, I'm just going to be a tough opponent."

Henin-Hardenne was especially pleased to have come back from a set down to beat Lindsay Davenport, the top seed, in a tight three-set battle to earn the clash with Sharapova.

The Belgian won 2-6, 6-2, 6-3 after an opening set full of unforced errors in a match, like the Russian pair's encounter, that failed to live up to expectations.

She said: "I'm very happy about this win because I think I came back from a very bad situation.

"She was dominating the match, for sure. She was hitting the ball very hard. She was confident in the first set, and I was a little bit too far from my baseline and I wasn't aggressive enough."

The Belgian has not been beaten at Melbourne Park since 2003, having won the Australian Open in 2004 and missing last year's tournament with a knee injury.

Henin-Hardenne twice double-faulted on break point to hand the early advantage to Davenport in a first set that featured six breaks of serve. The Belgian served a total of 11 double faults.

Davenport, the 2000 Australian Open champion, made a devastating 42 unforced errors, and was outplayed after the first set.

Henin-Hardenne acknowledged her clash with the Russian teenager would be difficult but was glad to be in the last four after injury and illness in the last couple of years.

She said: "It's going to be a tough match, it's a semi-final in a grand slam, it's always very difficult. But what a motivation for me. Just the fact that I'm here in the semis, I think that's great."