Head coach Michael Bradley knows how vital Friday's derby encounter is in terms of Connacht's overall season, as the westerners look to record back-to-back league victories for the first time since September 2006.
"From the start of the season we have been aware this fixture was coming at this time of the season, and that if it goes to form, it will be between ourselves and Ulster for the third (Heineken Cup) qualification place in Irish rugby so we have to win matches like these," he said.
"The momentum will come if we can get a result against Ulster, and that's a big step for us.
"If we can turn Ulster over, then we are looking at a realistic chance of qualification for the Heineken Cup.
"Otherwise the gap will open between us and it will be more of a struggle."
With New Zealander Nikora ruled out of the matchday squad, Liam Bibo, who played at out-half for Buccaneers last week, will provide cover for Keatley on the bench.
Young prop Jamie Hagan, a member of the 2007 Ireland Under-20 Grand Slam-winning side, has also been given a vote of confidence as he retains the number 3 jersey - starting ahead of former England international Robbie Morris who has recovered from a back injury.
Bradley is hoping for a large turnout of home support on Friday night, understanding what a difference that '16th man' can make at crucial stages of a tight match.
"I can't say it enough. Every person inside the gate is an advantage to us - they are the key ingredient.
"The noise and the crowd was fantastic last week, they really are brilliant and the lads responded.
"It is so important. If you only win a game by a hair's breadth, everything counts so I'd ask that Connacht supporters that if they are not doing anything, please come out and support us."
CONNACHT (v Ulster): Gavin Duffy; Brian Tuohy, Troy Nathan, Keith Matthews, Fionn Carr; Ian Keatley, Frank Murphy; Brett Wilkinson, Sean Cronin, Jamie Hagan, Andrew Browne, Bernie Upton, John Muldoon (capt), Ray Ofisa, Mike McComish
Replacements: Adrian Flavin, Robbie Morris, Mike McCarthy, Johnny O'Connor, Conor O'Loughlin, Liam Bibo, Aidan Wynne.