With first half tries from Ian Dowling and Damien Varley, and O'Gara adding the conversions and two penalties Munster lead the way in tonight's Magners League interprovincial clash at the halfway mark.
From a precautionary measure Felix Jones was stretchered off after 15 minutes after a clash of heads and he was replaced by Paul Warwick.
Connacht were down to 14 men in the final quarter after Troy Nathan received yellow after a late hit on Warwick, and the visitors added their first points when Ian Keatley kicked a penalty just before the break.
The second half was a dour affair that Munster dominated for large periods, Warwick and de Villiers adding the tries for the bonus point.
Munster: Felix Jones; Denis Hurley, Tom Gleeson, Jean de Villiers, Ian Dowling; Ronan O'Gara capt, Peter Stringer; Julien Brugnaut, Damian Varley, Tony Buckley; Mick O'Driscoll, Donnacha Ryan; Billy Holland, Niall Ronan, N Williams. Replacements: Mike Sherry, Wian du Preez, James Coughlan, Tommy O'Donnell, Duncan Williams, Paul Warwick, Scott Deasy.
Connacht: Gavin Duffy capt; Troy Nathan, Niva Ta'auso, Keith Matthews, Liam Bibo; Miah Nikora, Conor O'Loughlin; Brett Wilkinson, Adrian Flavin, Jamie Hagan; Michael Swift, Bernie Upton; Mike McComish, Johnny O'Connor, George Naoupu.
Replacements: Dermot Murphy, Ronan Loughney, Andrew Browne, Ray Ofisa, Ian Keatley, Kierran Campbell, Aidan Wynne.