The boyfriend who was with her that night - and is now her husband - also testified.
The couple was not able to identify Gadson, who is free on bail.
Gadson, a father of five, was arrested in January 2010 when police linked him to the case by his DNA - nearly 12 years after the alleged rape.
Defense lawyer James Ephraim Lee told the jury in his closing argument yesterday that Gadson and the woman had consensual sex and that she had lied and said she'd been raped because she needed an excuse for getting home late and missing her grandmother's curfew.
Lee argued that the woman's boyfriend wasn't even in the park at the time of the encounter but that he went along with her lie.
The lawyer pointed out what he called inconsistencies and contradictions in the couple's testimony, and noted that despite them saying there were two rapists, only Gadson's DNA was recovered.
"The commonwealth's story is stitched together by lies," said Lee, who argued that there was enough reasonable doubt for the jury to find Gadson not guilty.
Prosecutor Kelly Harrell scoffed at Lee's assertions. She said the couple - who were 18 and 15 and worked together at a McDonald's at the time - had no reason to lie or to want to relive that night's terror, which the victim had promptly reported to police.
"Do you think they're a team of con artists who crafted this story to pin a rape on a person they don't know?" she asked the jury.
"What happened to her was a rape by a stranger, a robbery by a stranger - two strangers. Unfortunately, only one is here," she said. The second alleged rapist has not been identified.
The jury will begin to deliberate Monday morning.
On Twitter: @MensahDean