Sharapova may have entered the match leading the head-to-head 6-1 but her form was patchy. At times she played magnificent tennis and was indeed the architect of beautifully constructed shots that carved out an open court and allowed her to seal points with breathtaking winners. Crosscourt, down the line, or overhead - it didn't matter. They all served the same purpose and worked as outright winners.
But there were also moments where the 24-year-old's game was plagued by inconsistency and that was all too clear in the opening set. Radwanska was the quicker out of the starting block, racing to a 4-1 lead but within the blink of an eye Sharapova had turned around her game to force a tie-break. And it was here that the former world no.1, sporting a lemon-coloured dress, really sprinkled the magic dust. She mixed up the game with attacking net play, precision lobs and crosscourt winners to steal the set 7-6(4).
Leading 2-0 in the second that all changed when Maria appeared to go off the boil. It was almost as though the Russian had little patience for the clay, hurrying through points in a bid to end them quickly and that was when the mistakes crept in. Radwanska, who had a heavily strapped left thigh, seized the advantage and broke. At 5-3 she was in possession of two set points but fluffed them both.
Sharapova broke back to 4-5 but was by no means out of danger and once again found herself defending set points against her - this time three. Radwanska netted the first, the second was cancelled out by a Sharapova winner and then another Radwanska mistake cost the Pole dearly on the third. She promptly lost that game and the next two to hand Sharapova the match and push the Russian one step nearer to her dream of achieving a career Grand Slam.
On Wednesday, Sharapova will face Andrea Petkovic in the quarter-final after the charismatic German came out on top of a three-set contest against Maria Kirilenko. The first set was three-quarters of an hour of grinding clay-courtery with almost every game going to at least one deuce. The no.15 seed, who had defeated Kirilenko already during this season's European clay swing at Rome and Strasbourg, secured the big points and broke three times, losing her own service just once, to take the opener 6-2.
The no.25-seeded Russian was far from overawed however and stormed back in the second, breaking Petkovic early and late in the set to level the match at one-all. And as the sun set on no.1 court, it came down to a decider. Petkovic sneaked a break to lead 3-2, pointing at her head and telling herself to focus with a steely glare that would have bent an opponent's racquet, let alone will, at 50 paces. The altogether more demure Kirilenko broke back almost immediately, showing the kind of accurate hitting that had blown Arantxa Rus - the surprise conqueror of Kim Clijsters - off the court two days earlier.
The decider became a shoot-out as dusk fell and the games on either side of the scoreboard approached the magic number of six. The self-styled "Petkorazzi" it was who broke in the ninth game and then with bravery, ferocity and above all focus served out for a 6-2, 2-6, 6-4 win which sees her into her second consecutive Grand Slam quarter-final.
She concluded the match with her now trademark backwards-sliding "Petkodance", but whether she will be able to moonwalk past Sharapova and into the semis is another matter.