The Japanese skater delivered a spectacular free skate, confirming his status as one of the favourites heading to Pyeongchang, with the 2018 Winter Olympic Games now rapidly approaching.
Toppling two-time champion Javier Fernandez, Hanyu had trailed by ten points sitting in fifth place after the short programme, a role reversal from when he surrendered a 12-point advantage to give the Spaniard a second successive title in Boston last year.
But the 22-year-old Olympic champion delivered his best performance of the season in Finland, scoring a year-best 223.20 points to scoop top spot, adding to his world title from three years ago.
"People say that other skaters are trying to catch up with me but you can see that I'm actually trying to catch up with other skaters," he said after nailing his four quads.
"I demonstrated everything I was capable of, my whole package. I wanted to do five quads but did not have enough energy."
Hanyu's combined score of 321.59 was enough to take top spot by just two points, as compatriot Shoma Uno maintained his second place from the short program. Jin Boyang rounded off the podium after leapfrogging Fernandez, with all four sailing over 300 combined points.
Elsewhere in Finland, Tessa Virtue and Scott Moir continued their excellent season form with a third ice dancing title, with the 2010 Vancouver Winter Olympic champions holding on despite Moir losing his footing during the dance final.
That helped Canada top the medals table, narrowly edging ahead of Japan on the final day of competition, with the pair adding to their world titles from 2010 and 2012.
"This is a great start and we're looking forward to building on it," said 27-year-old Virtue.
"It has been a successful season for us but we're not going to get carried away with that because we've never had a 'perfect season'."
Finally, Evgenia Medvedeva ably held off the chasing pack to successfully defend her women's title on the final day of action in Helsinki.
Leading after the short track, the advantage was not to be squandered as she hit top spot in the free skating too, finishing on 233.41 points.
That was more than 15 ahead of Kaetlyn Osmond in second place, while fellow Canadian Gabrielle Daleman also took her place on the podium.
A brilliant free skate from Mai Mihara saw her recover from 15th following the first discipline to finish fifth overall.
Read the original article on Eurosport: Brilliant Hanyu takes second Figure Skating world crown