Paul Burke's early penalty secured Munster their ninth straight Celtic League win in a low-scoring encounter at the Sportsground in Galway.
Connacht (0) 0
Munster (3) 3
The win enabled Munster to close within a point of leaders the Ospreys.
Defeat for Michael Bradley's Connacht ended their three-game unbeaten home run, and their hopes of a first win over their southern rivals in 18 years.
Burke controlled the game for Munster and he struck the match-winning penalty in the ninth minute.
A fierce front row battle ensued from the off, with the added spice of former Munster squad members John Fogarty and Peter Bracken packing down in Connacht
Coming under concerted scrum pressure, the home pack allowed 31-year-old Burke an easy first shot on nine minutes - and he duly obliged from 25 metres out.
The Munster number 10 was the game's leading light throughout, digging out field position for Alan Gaffney's visitors, as they irked out a number of try
chances towards the end of the first half.
On 33 minutes, a close range lineout drive off a Paul O'Connell take saw Gaffney's side shunt Connacht backwards and over their own line, but referee
Simon McDowell ruled out the score.
Munster were penalised for dropping their own drive and lost prop Marcus Horan temporarily to a head injury to compound their disappointment.
Burke's opposite number Paul Warwick had a lengthy chance to level the game on 51 minutes, but his 45-metre effort fell short of the posts as Connacht opened well.
Munster hooker Jerry Flannery's subsequent yellow card looked to have handed a clear advantage to the home side but the visitors' pack, containing six Irish
internationals, were outstanding with lock Paul O'Connell claiming six lineout steals.
Twelve months ago, Ronan O'Gara's 67th-minute penalty was the difference
between the sides in a 3-0 win in Athlone.
Connacht: Mostyn, Robinson, Yapp, Downey, McPhillips, Warwick,
Tierney, Hogan, Fogerty, Bracken, Short, Farley, Muldoon, Lacey,
J. O'Sullivan. Replacements: Jackman, Buckley, Myburgh, Swift, Keane, Elwood,
Munster: Cullen, Devlin, Storey, Holland, Horgan, Burke, Reddan, Horan, Flannery, Hayes, O'Callaghan, O'Connell, Keogh, Leamy, Foley. Replacements: Storey, Sheahan, Hogan, Quinlan, Prendergast, Payne, Lawlor.
Referee: S McDowell (Ireland)