Ulster's win was forged off a dominant scrum and a penalty try along with another Nick Williams score off the set-piece in the first half, before substitute Luke Marshall got over in the closing minutes.
Fly-half Paddy Jackson kicked 10 points and converted all four of his kicks at goal while Connacht, though they tried to replicate last week's stunning win over Leinster, just could not live with Ulster's power up front.
The game was Ulster's first at home since the farming tragedy which claimed the life of centre Nevin Spence, which was marked with a minute's silence before kick-off.
Ulster opened the scoring after 10 minutes with a Jackson penalty after a dominant scrum as John Afoa made hay early on against Brett Wilkinson - indeed Jackson's kick was the fourth penalty Connacht had conceded, two coming off the scrum.
Instead of kicking on from there, Ulster then struggled to break Connacht's defence down, though both Tommy Bowe and Andrew Trimble had chances before Ulster began to turn the screw around the half-hour mark.
Paul Marshall was held up over the line and then from a series of scrums near the Connacht line, first Chris Henry and then Williams seemed to get over.
But with the visitors' flanker Dave Gannon binned after the Henry drive, a score was inevitable and referee George Clancy awarded the penalty try which Jackson converted to make it 10-0 after 34 minutes.
Connacht then had a chance for points but Dan Parks missed the chance and right on half-time, Williams drove over for yet another try after Clancy had reversed a penalty against Connacht and Ulster had put the ball into the corner. Jackson converted and Ulster went off leading 17-0.
Connacht spared Wilkinson any more punishment by bringing on Denis Buckley at the break and the visitors finally got a decent line break when Robbie Henshaw brushed off Paddy Wallace but his pass to Fetu'u Vainikolo was forward, even though the winger appeared to be hit early by Marshall.
Ulster recovered and Jackson's penalty after Connacht were adjudged to have strayed offside made it 20-0 at the hour mark.
After that, the game became fractured as both sides emptied their benches - doubtless with European commitments in mind - until out of nowhere Bowe won a 78th-minute cross-kick from Wallace and substitute Luke Marshall skidded in.
Wallace missed the drop-kicked conversion but Ulster nonetheless stretched their advantage, with a game in hand over their rivals as they head into next week's opening European clash with Castres.
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