It was a defeat that hurt deeply. But when the two meet in the third round of the Australian Open here tomorrow, the British No.1 believes she is ready to compete with the world No.4 on her own terms.
"I think the first time I played her I just went in all guns blazing and didn't know what to do," Watson said yesterday, after saving three match points to beat Ksenia Pervak of Kazakhstan 4-7, 7-6, 6-2 in just over three hours.
"That killed me. I was so upset. I was playing at home in front of everyone and I just got wiped off the court. That wasn't a great experience. I just went for way too much. This time I'm coming in a different player, and I'm going to approach it differently.
At Wimbledon, Watson won just two games and Radwanska comes into the match in top form having won back-to-back warm-up tournaments.
But since her Wimbledon defeat, Watson has won her first WTA Tour title in Osaka and her two wins here will push her close to the top 40 in the rankings.
"She's a very different player to most of the girls," she said of Poland's Radwanska. "She's consistent, got great feel, so it's going to be another physical match. But I've played her before, so I've got that feeling. I feel more experienced and I feel more confident in my game. This is my second third round now, so I've been here. I'm just looking forward to playing her again."
Anyone who was packed in around Court No.8 here yesterday, a small court right on the extremities of Melbourne Park, would have witnessed another example of Watson's never-say-die attitude as she turned a near-certain defeat into another morale-boosting victory.
All at sea in the first set in a tricky wind, Watson was making numerous errors, particularly on the forehand, but slowly worked her way back into the match. Still, the tie looked over when Pervak, a former Australian Open junior champion, stormed to a 6-3 lead in the second-set tiebreak, giving her three match points.
"I thought, she's going to have to win it, I'm not going to give it away," Watson said. "So I just made sure I made every single ball and then suddenly it's my set point and I'm able to take that set."
From then on, it was all Watson as Pervak's head dropped and the Briton celebrated by hugging large numbers of the boisterous crowd. "They were just unbelievable," she said. "I think they really helped today."
Not blessed with the height of her fellow Briton Laura Robson, Watson has been working with her coach Mauricio Hadad to add power to her serve and come forward to shorten the points.
"Before she had a hard time coming to the net and now she's coming to the net when the ball is up in the air," Hadad said. "She'll have to do that more in the next years if she's going to be really successful."
If Watson loves the big stage, then Laura Robson absolutely revels in it, at least if last year's US Open is anything to go on, when she beat Kim Clijsters and Li Na on the way to the last 16.
The 18-year-old, just a few places behind Watson in the rankings, was due to take on Petra Kvitova, the former Wimbledon champion, this morning.
"I am just going to try and play my own game," Robson said yesterday, after losing her first-round doubles match with Hungary's Timea Babos.
"If I get sucked into defending all of her shots all of the time, then that is not going to work out very well for me. I have got to stay aggressive and just play as well as I can really. It is going to be really tough."
While Watson does battle tomorrow, most eyes will be on the blockbuster clash between Maria Sharapova, the No.2 seed and champion here in 2008, and the former world No.1 Venus Williams.
Sharapova crushed Misaki Doi of Japan 6-0, 6-0 to become the first woman to record back-to-back whitewashes since Wendy Turnbull here in 1985, while Williams, still battling Sjogren's syndrome, which causes chronic fatigue, cruised past Alize Cornet 6-3, 6-3.
But pity Sam Stosur, the Australian world No.9 and former US Open champion, who froze in front of her home crowd yet again and lost 6-4, 1-6, 7-5 to Zheng Jie of China.
Stosur led 5-2 in the third set, with two breaks of serve, but could not close it out. "At 5-2 up in the third, double break, it probably is a bit of a choke, yeah," she said, with typical honesty.