Ilves reclaimed top spot with a shootout win last time out, but their inconsistent form continued as they fell 4-3 at TPS Turku, whose own current form is the best in the division, as they have climbed to sixth with four wins in a row.
Over the first two periods, Ilves twice took the lead through Otto Latvala and Ilvari Heikkinen, but twice TPS struck back through Arttu Tuhkala and Jeremi Virtanen. In the final 20 minutes, the home side went ahead and stayed there thanks to Sisu Yliniemi and Vili Munkki, making Luke Henman's late goal nothing more than a consolation.
With Ilves' nearest challengers Assat not in action, the chance was there for Jukurit to return to first place for the first time since the first few rounds of the season, and it was a chance they took with a 3-0 win over Vaasan Sport, whose three-match winning run ended with a whimper as they drop to 13th.
The scoring was done and dusted by the midpoint of the match, as Louis Boudon gave the visitors a first-period lead before Justin Addamo and Jeremi Tammela extended the lead in the first 10 minutes of the second, while Jesper Myrenberg made 22 saves across the 60 minutes.
The Mikkeli side are one point clear of Lukko, who went second and knocked Ilves to third by getting the better of IFK Helsinki 3-2 after penalties - a third win in a row for the Rauma side and a three loss in a row for the struggling visitors.
HIFK weren't struggling when they went 2-0 up through Lassi Vanhatalo's shorthanded goal and Iiro Pakarinen's powerplay effort, but back came Lukko through Topias Haapanen and Felix Robert, before Leo Tuuva scored the first penalty of the shootout, which turned out to be the only goal.
Also on three successive losses after falling 3-2 after a shootout are the champions, Tappara, who remain in 11th place after becoming just the second team all season to lose to KooKoo. The Kouvola side remain bottom of the table despite winning the repeat of last season's play-off final.
These two won't be contesting the trophy again if their form continues, but that won't matter tonight for KooKoo, who responded to Vilho Vanhatalo's opener with goals from Vilmos Gallo and Arttu Pelli, only for Tappara to level in the final minute of regulation through Michael Lindqvist.
Veeti Miettinen and Aapeli Rasanen both scored in the shootout to send it to sudden death, and with his side's fifth penalty, Miska Siikonen found the net to give KooKoo two much-needed points.
SaiPa are fifth in the standings but only two points behind the leaders after they won the third shootout of the evening to beat Karpat 2-1. Eero Klintrup and Einar Emmanuelsson scored their penalties to give SaiPa a third straight win, as the home side overtook the Oulu side, who drop to seventh.
Pelicans have moved into the top 12 by putting their three-game losing run behind them with a 3-1 away win at Hameenlinna, handing the visitors a second loss in three after their positive run of form.