At 31, the Thiruvananthapuram native is now India's biggest medal hope at next year's Paris Olympics.
It was a glorious end to the night for the sport's superpower after the earlier disappointment of seeing their highly-favoured 4x400m women's team disqualified following a baton failure in the semi-finals
The world record holder and Olympic champion - unbeaten in more than two years - only sneaked into the final round of eight jumpers in last place before summoning a magical 15.08 metres on her final attempt.
The India pair lost to Denmark's Kim Astrup and Anders Skaarup Rasmussen in straight games.
World No. 11 Lakshya Sen, a winner of bronze medal at the 2021 edition, however, couldn't get past Thailand's Kunlavut Vitidsarn.
Kerr dug deep to stay in front and won in 3:29.38 with Ingebrigtsen, whose 3:27.14 run in Poland five weeks ago made him the fourth-fastest man in history, taking silver in 3:29.65.
The most successful Indian at World Championships with five medals, Sindhu lacked any sting in her attack and went down tamely 14-21 14-21 to old nemesis Nozomi Okuhara of Japan, a 2017 gold medallist and silver winner in 2019.
Prannoy, the world number 9, who reached the quarterfinals in the last two editions, saw off the left-handed Koljonen 24-22, 21-10 to extend his head-to-head count over the Finnish player to 3-0.
Sweden's Perseus Karlstrom won silver in 1:17.39, while Caio Bonfim of Brazil claimed the bronze (1:17.47) in 20-kilometre race walk.
Indian women's team won the team title at the world championship.