They have a game in hand on the team who edged them in last year's final, Team Wellington, who sit tied at the top after easing past Southern United 3-1.
The potent forward trio of Tommy Jackson, Ben Harris and Joel Stevens all struck for Wellington in a game where all four goals were scored in the first 38 minutes, with Jackson and Stevens both enjoying success against their former club.
Southern are now three points adrift at the bottom of the table after Tasman United ensured there were still some upsets in the round.
Tasman are now running a five-game unbeaten streak in their first season in the Premiership, having lifted themselves off the bottom of the table under new coach Davor Tavich.
They had former Wellington Phoenix standout Paul Ifill at the heart of their 2-1 win over Eastern Suburbs, with the 37-year-old scoring a double.
Ifill opened the scoring with a stunning strike, and then slotted a one-on-one with the keeper to cancel out a Suburbs equaliser from the penalty spot.
The result ended Suburbs' four-game unbeaten run and dropped them into fourth spot, a point behind Waitakere United, who edged Canterbury United 2-1.
Aaron Clapham struck an early blow for Canterbury, finishing off a quality counter-attack, but Dan Morgan and Keegan Linderboom responded quickly to give Waitakere a lead which they clung to for an important victory.
Canterbury now sit three points outside the playoffs in sixth, but things look brighter for Hawke's Bay United, who are just one point from a semifinal spot after thrashing the Wellington Phoenix Reserves 7-2.
The youthful Phoenix got on the scoresheet first, but Hawke's Bay scored the next six to make the game a rout. With two games remaining against Southern and Hamilton, Hawke's Bay will be favoured to take all six points and earn a playoff spot.
