The top-seeded Polish star had dropped only 10 games on her way to the semifinals, sweeping her first three matches in straight sets, but was fully taxed by the 71st-ranked Hampton.
"Actually, it was very tough and I was just happy to be two points better in each set," Radwanska set.
"It was really tough today. It was up and down the whole match," Wickmayer said. "I started well, but she came out really aggressive in the second set, particularly against my serve. I went to the bathroom and thought it all through and focused on playing my best tennis. I was lucky it went my way in the third set."