But in set two with the Russian somewhat more hesitant and reluctant to close out points, Radwanska served harder and hit deeper to jump out to a 5-2 lead.
Sharapova's serve continued it's second set pattern of inconsistency as serving to stay in the set, the Russian served up a doublefault before hitting an ace down the tee to reach 5-3.
More and more costly errors from Radwanska did not help her cause as she netted a dropshot to lose her serve for 5-4.
Connecting with and increasing number of winners and forcing more play, Sharapova held serve the broke to lead 6-5.
But two down the line groundstoke winners from Radwanska sent the second set into a tiebreaker as the score was even at 6 all.
In the tiebreaker, Ranwanska took a 2-0 lead before Sharapova won six points in a row to lead 6-2. An overpowering Sharapova forehand down the line return of serve forced a netted Ranwanska forehand on matchpoint number five.
Sharapova, one of the most powerful players of the WTA Tour, would finish the match with 42 winners.
In today's Toronto semifinals, the 4th seeded Elena Dementieva of Russia meets the 2nd seeded Serena Williams of the USA (3:00pm EST USA Live on ESPN2) while Sharapova takes on the 36th ranked Alisa Kleybanova also of Russia (7:00pm EST USA Live on the Tennis Channel).
In their first meeting ever, Sharapova could face tough opposition from Kleybanova, who plays a Lindsay Davenport-type power baseline game.