The Russian has long been the scourge of Halep, having won all of their five previous meetings.
Sharapova eventually made it six at the Singapore Indoor Stadium, having been made to sweat in a 6-4, 6-4 triumph that lasted nearly two hours.
The match started evenly enough as they traded blows until 4-4 in the first set – a point when world No 4 Sharapova upped her game, winning seven of the next eight games.
However, rather than collapse, No 1 seed Halep rallied impressively and closed the gap to 5-4, before she was defeated following one last break.
“It definitely got really tough,” said Sharapova. “I guess those are the moments you have to get through when you haven’t played in a long time, and against the number two player in the world these matches don’t come easy. It definitely showed until the end.”
Earlier, Flavia Pennetta recovered from Sunday’s defeat by Halep to secure a straight-sets win against Agnieszka Radwanska. The US Open finalist found herself 5-3 down in the first set, but came back to take the set and then the match, 7-6 (7/5), 6-4.
“I tried to be really focused, tried to hit the ball hard, be aggressive and not give her too much time to do her job,” Pennetta said.”