Olyslagers, a silver medallist at Paris 2024, pipped Patterson with a season best 1.97m after both failed to clear 1.99m in a dramatic finale inside the Nanjing Cube.
Yaroslava Mahuchikh was denied a clean sweep of gold medals having leapt 1.95m to finish third.
The Ukrainian star was bidding to reclaim her world indoor title having surrendered it to Olyslagers last year in Glasgow and came to China with a season best 2.01m.
But Mahuchikh, the current Olympic and world champion, could only clear 1.95m with Patterson, the 2022 world champion and world indoor silver medallist, winning silver on countback.
European indoor and outdoor silver medallist Angelina Topic finished fourth on 1.95m, with the 19-year-old Serbian – a rising star in the sport - narrowly missing out of medal contention.
Olajide makes senior debut in China
Great Britain's Funminiyi Olajide made her senior international debut in the long jump but missed out on reaching the latter stages as she finished tenth.
Olajide jumped 6.67m in Fayetville last month to qualify for Nanjing but could only record 6.41 after fouling on her second attempt.
"It was quite hectic out there trying to make it into the top ten," she said. "I was tenth and unfortunately, I couldn't advance and make it into the top eight, but it was fun just to be out there.
"It's made me very excited this being my first senior competition. I'm just focussed now on outdoors and world outdoors.
"This champs has taught me just to push 100% and not be anxious."
USA's Claire Bryant went on to win her maiden international title with a lifetime best of 6.96m, 13cm ahead of Switzerland's Annik Kalin with Fatima Diame nine centimetres behind for bronze.
However there was heartbreak for Bulgaria's Plamena Mitkova who was left screaming in agony after landing awkwardly on her fifth attempt.
The world under 20 champion was in the mix for a top-three finish but a hushed silence descended around the Nanjing Cube as she was taken away in a wheelchair clutching her right leg.
Later on Sunday Great Britain's Olympic bronze medallist Georgia Hunter Bell goes for gold in the 1500m, Neil Gourley competes in the men's final of the same distance and Scott Lincoln lines up in the shot put.
