University A beat Alhambra-Union 14-3 at Carisbrook on Saturday to win the club's 48th title.
It was a typically tight final with little free-flowing rugby.
In a stop-start game in which the ball rarely reached the wings, the students dominated possession and territory for large hunks of the game but the gutsy Alhambra-Union defence shut them out.
University A held a 6-0 lead at halftime and extended it early in the second spell when first five-eighth Tom Halse kicked his third penalty.
Luke Reihana replied for Alhambra-Union and the students led by only six points, 9-3, when Grant broke through the centre with six minutes to play.
Grant took a cut-out pass from Halse and found himself in a gap.
He ran on an angle to the corner and was tackled 15m out.
The students grabbed the ball from the breakdown and former All Black Adam Thomson brushed off two tackles to score the only try of the game.
"It was a starter move to see what would happen," Grant (22) said.
"I found a hole and just kept running."
It was the first premier championship banner as a coach for former Scottish captain John Leslie, who won four banners as a player for University A from 1991 to 1994.
"The game was even and there was not a lot free-flowing rugby," Leslie said.
"We got an early lead and held on to it. We went into our shell a bit but did enough to win."
The defence of both sides was tight and difficult to penetrate.
The students dominated possession and territory for first 20 minutes and attacked the Alhambra-Union line.
They dominated the lineout throughout the game and won the count 15-9 through the efforts of locks Josh Townsend and Hoani Matenga.
The students took three takes off Alhambra-Union throws.
It was clean ball the backs tried to use.
But when this failed because of the defensive wall Alhambra-Union put in place, they attacked through the forwards with marauding play by the loose trio of Paul Grant, Brad Cameron and Thomson.
Thomson was the outstanding player on the paddock with his fierce tackling, aggression at the breakdown and marauding play with the ball in hand.
The game changed after 20 minutes when Alhambra-Union attacked through the forwards, and made ground with the pick and go through its strong front row of Scott Manson, Liam Coltman and Ben Pereira.
This was an area of the game in which Alhambra-Union held the advantage, but the attacks started too far out and seldom threatened the line.
Alhambra-Union also held a slight advantage with its efficient technique in the scrum and loose forwards Regan Turoa and Waharai Waitohi were tigers on defence.
Thomson and halfback Sean Romans were members of the 2004 University A team that won the banner and they used their experience to keep the students in front through a torrid second spell.
Club final
The scores
- University A 14
Adam Thomson try; Tom Halse 3 pen
- Alhambra-Union 3
Luke Reihana pen
Halftime: University A 6-0.
Referee: Ross Barnett.
Crowd: 2500.