However, it was the Blues who drew first blood on 12 minutes. Initially, centre Brian Murphy forced a good turnover on halfway.
After quick ball was shovelled out to the left, winger Jerome Harimate showed great acceleration to evade two tackles before feeding scrum half Caolin Blade on his inside shoulder who crossed under the posts. Out-half Ross Shaughnessy converted for a 7-0 lead.
Bective continued to press, with veteran out-half Barry Lynn keeping the visitors guessing by varying his play. But the 'Wegians defence held firm, and they struck a decisive blow when they doubled their lead with their second meaningful attack just after the half hour.
Not for the first time this season, the attack originated from a lineout maul which rumbled up fully 20 metres to the try-line, before the Blues were held up in goal.
However, a forward shunt by another powerful scrum meant that Blade had to simply flop on the ball on the try-line - only to be denied by the infringing Bective back row, and referee David Wilkinson had no option but to award a penalty try. Shaughnessy converted to make it 14-0, which was how it remained at the break.
In the second half the pattern continued with both sides trying to play free-flowing rugby. However, the 'Wegians defence kept their shape to keep the Bective attack at bay, and they showed their attacking prowess yet again when they scored try number three in the 53rd minute.
It came following a superb breakout of defence where veteran John Cleary linked well with promising rookie and replacement winger Ciaran Gaffney to attack the Bective 22.
Having stretched the home defence, the Blues were yet again held up over the line, this time captain Brian McClearn being denied.
It was brief respite for the hosts as the 'Wegians scrum once more drove forward, giving number 8 Eoin Rooney the chance to claim his first try of the league campaign. Shaughnessy converted again to put 'Wegians out of sight
The entertainment continued into the final quarter as Bective went in search of points.
However, 'Wegians determination to hold firm was epitomised by an epic tackle by tireless prop Ja Naughton who pummelled Lynn when the out-half was about to ground the ball in-goal for a try, only to knock on with the force of the impact.
Winger Harimate almost stole a bonus point late on with an outrageous basketball-style interception near his try-line, before galloping fully 80 metres downfield only to be hauled down by the chasing defence.
Battling Bective finally got their reward when a patient series of phases saw Gearoid O'Grady cross near the posts for a converted try with eight minutes left.
Then, right on 80 minutes, the Dubliners scored a second try when Mark Joyce went over in the corner to reduce the gap to 21-12.
Nonethless, it was too little, too late and indeed the buoyant Galway club closed out the game on the attack threatening to add a bonus fourth try.
But referee Wilkinson's whistle sounded to end the contest and ensure that the Division 2A crown is heading to Crowley Park, where it will be presented after Wegians' final league game at home to Rainey Old Boys on Saturday, April 12.
GALWEGIANS: John Cleary; Colin Conroy, Rory Parata, Brian Murphy, Jerome Harimate; Ross Shaughnessy, Caolin Blade; Ja Naughton, Conor Muldoon, Doran McHugh; Dave Nolan, Brian McClearn (capt), Anthony Ryan, Eddie Earle, Dan McCabe.
Replacements: Ross Fitzgerald, Jason East, Jack Dinneen, Barry Lee, Ciaran Gaffney.