Ulster cemented Connacht's position at the foot of the Magners League table with an 18-6 victory in the basement battle at Ravenhill on Friday.
The conditions played a big part in a mistake-strewn and tense affair at, but Ulster did just enough to take the crucial points and put considerable daylight between themselves and Connacht.
Second-half tries from Ulster prop Tom Court and wing forward Matt McCullough ensured that Matt Williams' side also denied the visitors a losing bonus point to put Ulster eight ahead of the western province with four games remaining for the Northern Irish outfit.
It should be enough to secure Heineken Cup rugby for Ulster for another season, but Connacht will be deeply disappointed at the outcome after Andy Dunne missed four kicks at goal when the home side seemed there for the taking.
Ulster could hardly have made a more unsettled start when number eight Stephen Ferris was sin-binned in the seventh minute for recklessly diving over a ruck, though the visitors failed to take immediate advantage during the rainswept start to the game when Dunne's drop-goal sailed wide.
However, the Connacht's out-half made amends just before the quarter-hour mark with a penalty after Ulster failed to roll away at a ruck.
A minute later Connacht were also down to fourteen men when prop Robbie Morris was also shown yellow after an offence at the restart.
Ulster number ten Niall O'Connor failed with the penalty attempt, but then put the ball between the sticks three minutes before the break to draw Ulster level.
As a miserable first-half petered out, Dunne then hit his second penalty attempt wide.
The pivot then missed two penalties in succession shortly after the restart - the second seeing him immediately substituted by Troy Nathan - before two charge-downs brought Ulster deep into Connacht territory from where, after five minutes camped near the visitors' line, Court was driven over.
Paddy Wallace, now at fly-half in place of the substituted O'Connor, converted and Ulster had kick-started their game.
Wallace then landed a 66th-minute penalty to make it 13-3 but Nathan got Connacht back into losing bonus territory with a 71st-minute penalty.
It was shortlived, however, as McCullough had the final say when he was driven over for an unconverted effort three minutes from time.
Tries: Court, McCullough
Pen: O'Connor, Wallace
Pen: Dunne, Nathan
Yellow card(s): Ferris (Ulster - 7 mins), Morris (Connacht - 26 mins)
Ulster: 15 Bryn Cunningham, 14 Tommy Bowe, 13 Andrew Trimble, 12 Paddy Wallace, 11 Mark Bartholomeusz, 10 Niall O'Connor, 9 Isaac Boss, 8 Stephen Ferris, 7 Kieron Dawson, 6 Matt McCullough, 5 Carlo del Fava, 4 Justin Harrison, 3 Tom Court, 2 Rory Best (c), 1 Justin Fitzpatrick.
Replacements: 16 Neil Brady, 17 Bryan Young, 18 Ryan Caldwell, 19 Roger Wilson, 20 Kieran Campbell, 21 Rob Dewey, 22 Marc McCrea.
Connacht: 15 Gavin Duffy, 14 Matt Mostyn, 13 Mel Deane, 12 Keith Matthews, 11 D Riordan, 10 Andy Dunne, 9 Conor O'Loughlin, 8 Colm Rigney, 7 Jonny O'Connor, 6 John Muldoon, 5 Andrew Farley (c), 4 David Gannon, 3 Robbie Morris, 2 Andrew Flavin, 1 Brett Wilkinson.
Replacements: 16 John Fogarty, 17 Ronan Loughney, 18 Andrew Browne, 19 Liam Casserly, 20 Connor McPhillips, 21 Troy Nathan, 22 Darren Yapp.
Referee: Chris White (England)
Touch judges: Colin Stanley (Ireland), David Wilkinson (Ireland)
Television match official: Marshall Kilgore (Ireland)
Assessor: Tom Aplin (Ireland)