Munster took the lead thanks the boot of scrum-half Brian Haugh, who split the posts three times inside a quarter of an hour.
Munster ran in the only try of the half, full-back Darren Sweetnam darting over in the corner to hand Munster a 14-0 lead at the interval.
Leader got Connacht off to a dream start in the second half when he crossed under the posts six minutes after the break. The flyhalf then produced the moment of the game, breaking from just inside halfway to dot down under the posts again. But three minutes later Jermyn finished off a brilliant move and the home side held out for a hard earned victory.
Munster: D Sweetnam (Bandon Grammar); R Jermyn (Midleton), H McNulty (Dublin University), R Scannell (Dolphin), A Enright (Abbeyfeale); T Kiersey (Waterpark), B Haugh (Young Munster); N Horan (Crescent Comp), W Foley (Dolphin), B Scott (UCC); S McCarthy (Shannon), J Madigan (Charleville); J O’Donoghue (U.L. Bohemian), D Ryan (Young Munster), J Fitzgerald (PBC).
Replacements: D Hartnett (PBC) for Horan (74), J Kind (Dolphin) for O’Donoghue (61), D O’Connell (UCC) for Madigan (61), S O’Leary (Young Munster) for Scannell (78), J McInerney (Garryowen) for Jermyn (79).
Connacht: A O’Meara; C Fitzgibbon (Buccaneers), M Roche (Lansdowne), R Casey (Naas), P O’Neill (UCD); D Leader (Galwegians), B Digby (Buccaneers); A Boland (Lansdowne), J Connolly (Monivea), J Dever (Corinthians); S O’Brien (Galwegians), U Dillane (Corinthians); A Connaughton (Buccaneers), P Maxwell (Buccaneers), J Connolly (IT Carlow).
Replacements: N Fitzgerald (Shannon) for Maxwell (80), J Conroy (IT Carlow) for Connolly (54), B Teape (Buccaneers) for Dever (47), M Mannion (IT Carlow) for Dillane (58), L Satchwell (Buccaneers) for Digby (78), C Murtagh for Connaughton (50), C Joyce for O’Neill (73).
Referee: R Kerr (IRFU).