A 7-5, 6-4 win took Radwanska through to the last eight in south-west London for the fifth time in her career, where she will meet WTA Rising Star Madison Keys.
Radwanska went into the grass court season short of wins and belief following a testing first half of the year. However, having played herself back into form with deep runs at the tune-up events in Nottingham and Eastbourne, her cerebral game has been back to its best at the All-England Club.
In the previous round, Jankovic upset defending champion Petra Kvitova, and she picked up from where she left off early on against Radwanska, building a 3-1 lead. However, she was unable to maintain this level and as the contest wore on it was Radwanska that began to look the more likely winner.
Having pinched the first set, the Pole held her nerve in a topsy-turvy second, making it over the finishing line when Jankovic sent a tired forehand long.
Ever since lifting the girls' title a decade ago, Radwanska, whose anachronistic style is ideally suited to the well-manicured lawns, has never hidden her love of tennis' most storied venue. In the years that have followed, she has appeared in the quarterfinals, semifinals and in 2012 made it all the way to the final.
Meeting her next on this latest quest for the Venus Rosewater Dish will be Keys, who earlier in the day ended the run of qualifier Olga Govortsova, 3-6, 6-4, 6-1.
Keys was out of sorts in the opening set, but once she had settled down to edge a close second her powerful game really began to purr.
"I think I was a little bit nervous at the beginning," Keys said. "She was playing really well and I wasn't playing as smart as I wanted.
"But I sat down and gave myself a talking to, I started playing my shots and kind of got myself back in control."
Two years ago, Keys' athletic game and easy power earned rave reviews at Wimbledon, as well as some favorable comparisons with one of her childhood idols, Serena Williams. On that occasion, her run came to an end at the hands of Radwanska in a high-quality third round encounter that left a lasting impression.
"I think she's an incredible fighter. She is a great mover, and her hands are unbelievable," Keys added. "You know, I feel like she's always there. She makes you play four extra balls. You know, she's a really tough opponent."