O'Connell, who still harbours hopes of going on the 2013 Lions tour to Australia this summer, was joined on the scoresheet by Damian Varley, the hooker helping himself to two tries.
And fly-half Ronan O'Gara kicked the rest of the points as Munster halted a mini-losing run that had seen them not win in their last three games, and recorded their first victory at Musgrave Park since downing Edinburgh on home soil back on February 9 in the process.
Connacht burst into life were stopped just metres short of the tryline as they looked to record a fourth-straight league victory for the first time since September 2002.
But Connacht have not won on Munster soil since 1986 and the home side soon woke up and after ten minutes of dominant possession O'Connell had the first score of the game following three reset scrums, O'Gara adding the conversion.
Things went from bad to worse for the visitors just three minutes later as Mick Kearney was sent to the sin-bin for a late tackle on Munster fly-half O'Gara.
And the lock's dismissal was felt almost immediately as Munster went over just a minute later with Varley making the most of a powerful scrum, this time O'Gara failing to add the extras.
Connacht slowly started to get back into the game and two breaks from Danie Poolman and Kieran Marmion lifted the travelling contingent.
But as half-time loomed Connacht were pinged for being off their feet in the tackle and O'Gara knocked over the penalty for a 15-0 half-time lead.
Connacht brought on Mike McSharry after the restart for his 150th cap but it failed to turn the tide as Munster soon had their third try of the evening, and Varley his second, O'Gara adding the conversion for a 22-0 lead.
A raft of changes for both sides disrupted the flow of the game in the second half as Connacht tried their best to salvage something from the game.
And with ten minutes left captain Gavin Duffy looked like doing exactly that as he made a great break for the line, but Munster got men behind the ball to keep them at bay.
Munster weren't done there though and attentions quickly turned to grabbing that fourth try for a bonus point but it wasn't to be as Connacht held firm.
|Munster Rugby Score Card|
|Connacht Rugby Score Card|