After successive league draws, KuPS were under pressure to pick up three points at home to struggling Haka despite a long and fruitless trip to Kazakhstan in midweek, where they were knock out of the UEFA Champions League against Kairat Almaty.
But the pressure did not show, and they were in front after just 11 minutes when Bob Armah played a low cross over for Agon Sadiku to tuck home.
Sadiku was forced off with only 27 minutes on the clock, but KuPS needn't have worried, as it took his replacement, Mohamed Toure, to make it 2-0 just four minutes later.
Haka made changes of their own at the break, which paid dividends as they were back in contention six minutes after the restart through Danila Bulgakov. But hopes of a comeback were thwarted just before the hour mark, as Toure notched his second of the game.
The 3-1 win for KuPS has seen them move third, a point behind Ilves and three shy of Inter Turku. The top two are both in action on Monday, with Inter facing HJK, who have dropped to fourth. Haka are now winless in five and remain in 10th.
Haka have at least avoided dropping further down the table, after 10-man AC Oulu were beaten 1-0 at home to Jaro.
Onni Tiihonen was booked with 10 minutes of the half remaining, and shortly after the visitors went in front when Sergei Eremenko set up Albin Bjorkskog.
Two minutes after the break, Tiihonen's afternoon and Oulu's chances of a comeback got worse as the midfielder picked up a second yellow card. The 10 men could not find a way through and fell to a defeat for only the second time in seven in all competitions.
They remain 11th, while a first victory in five takes Jaro up to eighth.
On Friday night, two sides who cannot buy a win surprised no one by playing out a stalemate, as VPS drew 1-1 at home to Mariehamn.
Martti Haukioja broke the deadlock for the home side with 63 minutes played, but the Vaasa side were denied a first win in eight games in the 95th minute, when goalkeeper Rasmus Leislahti put through his own net.
The late equaliser secured a fourth draw in their last five for the Aland islanders, but they remain winless in six. They drop a place to ninth, but stay only three points behind sixth-placed VPS in the battle for the Championship Round places.
