Off-spinner Gardner finished with 8-66 on the final day on Monday - the best innings haul for Australia and the second-best overall - while her match figures of 12-165 were also the second best behind Shaiza Khan's 13-226 for Pakistan from 2004.
She had taken a blow to her bowling hand during slips practice in Australia's three-day warm-up match and did not bowl before the test.
"My finger obviously bent backwards where it's probably not supposed to. It's almost stretched that ligament a little bit," Gardner said. "Adrenaline does funny things and I completely forget about it as soon as the ball was in hand.
"So as soon as I wasn't bowling (at Trent Bridge), I put a splint straight on it, just to protect it because in the field is where I'm more likely to get hit.
"It was quite frustrating but because I didn't get that match practice in before the test."
Gardner, who had dismissed key players Tammy Beaumont, Heather Knight and Natalie Sciver-Brunt on the penultimate day, said she spent a largely sleepless night visualising how she was going to remove England's remaining five batters.
"I was awake at 3 a.m. thinking about bowling, which was a bit tragic," Gardner said. "I was wide awake, literally thinking about how I was going to get the batters out and I've never done that before."
Australia earned four points in the multi-format series as they bid to retain the Ashes. The teams next meet in a three-match Twenty20 International series beginning on July 1st at Edgbaston.