
The Russian fifth seed, two times a Grand Slam champion, handed world number one Henin her first loss since Wimbledon. The victory in one hour, 38 minutes was only the third for Sharapova in nine meetings.
The women last met at the WTA season finals in Madrid, Henin winning a marathon final in three hours, 20 minutes. Henin's winning run ended at 33 matches.
Sharapova next faces Jelena Jankovic, who claimed her third career Grand Slam semi as the dismantled petulant holder Serena Williams 6-3, 6-4 in a dazzling display.
Sharapova broke in the second game of each set for 2-0 leads as Henin had trouble with the Russian's all-court attack.
The Russian lifted the first set after 61 minutes by winning a 10-minute game comprising four deuces on her fourth set point, a missed volley by Henin.
The scenario for the second set was similar, with Sharapova raising her level to cut off any attempt at redemption from the Belgian.
"I felt I was in a bubble," said Sharapova. "I didn't pay attention to how many she had won, it was scary.
"I just went to the court and did the right things to beat such a great player."
Smiling Serb third seed Jankovic has now reached the final four in Melbourne, New York and Paris since 2006. Victory - marred by ten breaks of serve - boosted her record against Williams to 3-2.
"I've beaten the Williams sisters a couple times. But here it is very special, because last year actually in this tournament in the fourth round I lost to her," said the winner.
"Getting revenge it feels so good. I'm so happy to be in the semi-final, having no expectations, having injuries, and not really thinking that I can go far.
"But I just played one match at a time, and I really don't know how I'm doing, but I'm in the semis, and it feels great.
"This doesn't happen every day, I'm glad to get another win against her."
Williams, who reportedly smashed a racket during practise earlier in the day, was never on her game, holding serve a mere three times.
The American also handed over a fifth double-fault for a Jankovic match point, which the Serb converted as Williams sprayed a forehand wide after one hour, 39 minutes of pure frustration ended by a 34th unfolded error.
Jankovic has been dealing with a run of injures since the start of the month. She said that merely strengthens her desire.
"Players think that I'm injured and cannot play. But I'm like a wounded animal, but I still keep going."
On the men's side, Rafael Nadal marked a personal milestone as he booked into his first Australian Open semi-final at the expense of fighting Finn Jarkko Nieminen 7-5, 6-3, 6-1.
Nieminen gave the Spanish second seed trouble in the first set, forcing Nadal to save two set points. But the thrill of the challenge was just the tonic the world number two needed to take charge from that point.
But Nadal is still questioning himself as the business end of the year's first major approaches.
"Maybe I didn't play my best match, my best tennis today. But it was enough. I'm happy about the victory, I didn't play badly."
Nadal becomes the fourth Spaniard to advance to the Melbourne semi-finals after Andres Gimeno, Carlos Moya and Juan Carlos Ferrero, last Spanish semi-finalist in 2004.
DPA