At the bottom of the table, Instonians remain five points from safety after losing at Glenanne.
In the women's IHL Ulster Elks were beaten by Ards and remain a point behind Pembroke Wanderers in the battle to avoid relegation.
Pegasus revived their chances of a top-four finish with a win over Loreto.
With a place in the Irish Senior Cup final secured, Banbridge remain on course for a potential domestic treble after a 4-1 home win over Pembroke Wanderers maintained their two-point advantage at the top.
Jonny McKee scored twice with the other goals coming from Eugene Magee and Ross Beattie.
Three Rock Rovers came from 2-0 down to beat Monkstown 3-2 to keep up the pressure on Bann while Lisnagarvey are only a further point off top spot after a 6-1 home win over Cork C of I.
Matthew Nelson scored twice for Garvey with Daniel Buser, James Lorimer, Timmy Cockram and Sean Murray netting the others.
Nelson and Murray will be hoping to be named by Irish coach Craig Fulton on Monday in his squad for World League 2 at Stormont next month.
Instonians were beaten 4-0 by Glenanne and are five points behind Railway Union at the foot of the standings but the Ulster side have two games in hand.
In the women's league, Ards edged out Ulster Elks 2-1 at Londonderry Park after goals from Chloe Brown and Tamara Macleod with Danni Wilson's last-minute reply a mere consolation.
The win leaves the Elks a point behind Pembroke who were beaten by leaders UCD.
Pegasus are up to fifth and back in the race for the end of season play-offs after a 1-0 win at Loreto thanks an early Rachael McMillan goal.
The Belfast club are just two points behind the Dublin side with fourth place guaranteed a spot in the end of season play-offs.
Two goals from Irish international Anna O'Flanagan were enough for Monkstown to beat Railway Union 2-1 and they are just a point behind UCD at the top with a game in hand.
The top three in the Men's Irish Hockey League, Banbridge, Three Rock Rovers and Lisnagarvey, all won on Saturday to extend their advantage over the pack.