To make matters worse for Inter Turku, their 2-2 stalemate on Thursday evening came away at bottom-of-the-table KTP who have won just twice all season and are without a win in four.
All four goals in Kotka arrived in the first half - the visitors looked set for a comfortable afternoon just seven minutes in when Loic Essomba found the net for the first time in four matches.
With 28 minutes on the clock, KTP hit back through Rangel, only for Axel Kouame to lay on his second assist for Essomba just three minutes later to restore Inter's advantage.
However, a crazy three minutes turned into a mad five, as a second goal in as many games for Assane Seck levelled matters once more.
But that was where the scoring ended, as KTP held on for just their 11th point of the season, while the Turku side saw their two-match winning run end.
The leaders' draw left the door open for Ilves, who would go a point clear at the top with victory away at Jaro.
The home side made the Lynx work for it, but the only goal arrived just before the hour mark, as teenager Jardell Kanga notched for the third time this season.
Hopes of a comeback for Jaro were dealt a blow late on when the league's top scorer Kerfala Cissoko was shown a straight red card. As has often been the case this season, when Cissoko doesn't score, Jaro don't score, and that was true again this time as Ilves held on for the 1-0 win they needed.
It's two defeats in succession for the Jakobstad side, while the men from Tampere are five unbeaten in domestic competition.
Another plus for Ilves this weekend is they also put further distance between themselves and third-placed KuPS, who drew 1-1 with VPS.
The champions were dealt a blow inside the first 30 minutes when Samuli Miettinen was sent off, but the hosts failed to take advantage, and the 10 men went in front through Mohamed Toure with 10 minutes to play.
But with a minute of the 90 remaining, Yassin Daoussi popped up with an equaliser for the home side, who snapped a four-match losing run, while KuPS have been held for the second successive league game, and are now four points off the pace.
HJK built on their superb midweek comeback against NSI Runavik with a 3-1 victory over AC Oulu. Benji Michel and Kai Meriluoto gave the Helsinki side a comfortable advantage at the break, before Jere Kallinen added a third 11 minutes into the second half.
Mikko Pitkanen grabbed a 90th-minute consolation for Oulu, who are now just a point clear of KTP at the foot of the table after a first defeat in four. A second win on the bounce has helped HJK move within two points of KuPS.
Still a point shy of HJK and determined to keep a five-way title race alive are SJK, who picked up a 3-1 win of their own over Gnistan, who are now eight points further back in sixth.
Matias Ritari put visiting Gnistan ahead in the first half, and that was how it stayed until the 59th minute, when Kasper Paananen equalised. From then on, it was all SJK, whose Rasmus Karjalainen scored twice to extend the Kerho's unbeaten Veikkausliiga run to six matches.
Finally on Monday evening, eighth-placed Mariehamn picked up a third draw in a row by coming from behind to draw 1-1 with ninth-placed Haka, who are three games without a win.
Simon Lindholm struck early for Haka, but Korede Adedoyin levelled matters for the Aland islanders in the second half.
