Venus Williams was back in the pink as she thumped Wimbledon semi-finalist Kirsten Flipkens to reach the second round of the US Open.
It has been another tough year for the American, who won her first match for more than four months in Cincinnati last week.
But on Monday, with pink hair knotted above her head, she kept the momentum going and romped to an impressive 6-1 6-2 victory over the 12th seed.
Explaining the transformation, Williams said: "My serve was a lot better. In Toronto I wasn't really feeling that great about my serve. Just coming back I've had to do a lot of work on my serve.
"Honestly I think that made a huge difference. I think I was serving in the 40 percentages all my matches this summer, so it was very challenging. You can only go up."
Williams announced two years ago in New York that she was suffering from the auto-immune disease Sjogren's Syndrome, while at 33 she is one of the oldest women on the tour, but her appetite for tennis shows no sign of diminishing.
She said: "I stay positive because I know I can play great tennis.
"Sometimes you just have to go through more than what you want to go through. Sometimes you have to have losses. When I have losses, it always motivates me a lot to do better and to work harder.
"So I realise that I haven't had a lot of chances to play healthy this year, so I'm just going to have to keep working my way into it maybe more than some of the other players, but I know I can do that."
Radwanska is seeded third following the withdrawal of the injured Maria Sharapova and she coasted past Silvia Soler-Espinosa of Spain 6-1 6-2.
The US Open is the only grand slam at which Radwanska has not reached the quarter-finals, while her build-up included an unscheduled trip back to Poland for the funeral of her grandfather.
She was forced to miss her quarter-final in Cinncinati to travel home, but is carrying plenty of confidence into the year's final grand slam.
Radwanska said: "I really had a lot of good matches coming here. From Stanford to Cincinnati a lot of matches, and it was really a good run. Especially because every week it's different conditions and different balls, different courts.
"So it's a really tough period, I think, for the players, and I think that I prepared very good. I'm ready now to play here, and hopefully I can play the same good tennis."
Wimbledon runner-up Sabine Lisicki had a tougher time against Vera Dushevina but came through 6-2 7-6 (7/3) while American Lauren Davis suffered the dreaded 'double bagel' 6-0 6-0 defeat against 18th seed Carla Suarez Navarro.