After Inter Turku were held by Gnistan on Friday, Ilves knew they would move within a point of the leaders if they could return to winning ways against Haka.
They made a positive start when Roope Riski put them ahead from the penalty spot, before a second yellow card for Nicolas Gianini Dantas reduced the hosts to 10 men after 39 minutes.
Ilves made the man advantage count early in the second half through Maksim Stjopin, then a Niklas Friberg own goal and another in added time from Teemu Hytonen but the gloss on a 4-0 win.
SJK's poor run is well and truly over as they picked up a third win in a row, thrashing Mariehamn 4-1 to move fourth on 24 points - two behind Inter and KuPS.
The home side were rampant, scoring three times in the opening 18 minutes, courtesy of Jeremiah Streng, Kasper Paananen and an own goal from Michael Fonsell.
Just after the hour mark, Elias Mastokangas added a fourth, before Korede Adedoyin grabbed an injury-time consolation for Mariehamn, who remain in eighth place.
Fresh from a midweek win in the Suomen Cup over SJK, bottom side AC Oulu made it two from two in all competitions thanks to a 2-1 win over VPS in a match which kicked off at 23:00 local time.
The late start seemed to be suiting VPS better, as they took the lead via a Nicolas Fleuriau penalty. But back came Oulu, who equalised before the break with a strike from Justin Rennicks.
Rennicks was clearly enjoying the Finnish midsummer nights, as it was he who scored the winner just past the hour mark. He therefore scored the first goal of his brace on Saturday and the second on Sunday!
However, Oulu were unable to move off the foot of the standings, as KTP got the better of Jaro, 3-2.
Goals from Assan Seck either side of the break were the difference makers for KTP, for whom Petteri Forsell equalised from the penalty spot after Kerfala Cissoko had given Jaro the lead.
Michael Ogungbaro pulled a goal back from the visitors in added time, but it was too little too late.