When the draw came out a week ago it was the match-up everyone was waiting for - both multiple Grand Slam champions, both former No.1s, both BNP Paribas Open winners too. And the rivalry couldn't have been closer, with Azarenka just edging Sharapova in 13 previous meetings, 7-6.
Things couldn't have been closer in the first set, with Sharapova rallying from a break down to take it in an hour and seven minutes, 6-4. Once that was out of the way she went into cruise control, storming out to a 5-1 lead in the second set - but that's when Azarenka's fighting spirit came very alive.
After breaking back to close the gap to 5-2, Azarenka fought off four match points in the next game and held to make it 5-3, and then fought off a fifth match point at 40-15 on the Sharapova serve.
The No.2-seeded Sharapova finished the No.32-seeded Azarenka on match point No.6, 6-4, 6-3.
"I think she played well. I have to give her credit. Obviously she's No.2 in the world for a reason," Azarenka said. "She was just more consistent than I was in the important moments. I created too many opportunities not to take them, and you just cannot afford to do that against a player like Maria."
"It's just great to see her back healthy and playing at a good level again," Sharapova said of the Belarusian. "She had a few comebacks last year, but it seems like she's really back on track now.
"I actually didn't feel like I played my best tennis. But I was competitive. I was there. I feel like I did everything I had to do in order to win the match, which is sometimes the most important thing."
Pennetta is now on an eight-match winning streak at the BNP Paribas Open, winning six in a row to capture the biggest title of her career here a year ago, and adding two more wins to that total this year.
Sharapova and Pennetta are tied in their head-to-head, 2-2. All four career meetings have gone to three sets, and Pennetta has actually won their last two - they haven't played since 2011, though.