Tramore's John Mitchell shot a level par 72 to lead the Munster Seniors Open by a shot after the opening round at Waterville Golf Links.
The Irish Senior international followed 10 pars with a bogey at the 11th but eagled the par-five 13th to move into the red.
Bogeys at the 14th and 17th left him over par again but he birdied the 18th for the only par round of the day as McGimpsey made four birdies for a one over par 73 that left him tied for second with Birr’s Billy Donlon.
Defending champion Tom Cleary shot a 74 with a bogey at the last for fourth spit on there over with Skerries' Michael Ahern fifth after a 75.
Cleary won the title last year after a marathon seven hole playoff with Bandon's Donal O'Donovan, who is tied 10th after a 77.
MUNSTER SENIORS AMATEUR OPEN CHAMPIONSHIP. WATERVILLE
SPONSORED BY CLARION HOTEL LIMERICK
ROUND 1 RESULTS CSS = 75
72 John Mitchell (Tramore)
73 Billy Donlon (Birr), Garth McGimpsey (Bangor)
74 Tom Cleary (Cork)
75 Michael Ahern (Skerries)
76 Michael Quirke (Doneraile), Neal Pitches (New Zealand), Richard Brooker (Skerries), Morgan Pierse (Grange)
77 Seamus Ward (Laytown & Bettystown), Val Smyth (Co. Louth), Donal O' Donovan (Bandon), Alan Lilley (Ballyclare), Mervyn Eager (Lucan)
78 Kevin Sheehy (Athlone), Michael Coote (Tralee), Gerard O'Sullivan (Tralee), Arthur Pierse (Tipperary), Noel Mannion (Dun Laoghaire), Gregory Young (Lahinch)
79 Neil Hughes (Gog Magog), Maurice Kelly (Naas), Foley Gort (Castletown), Donal O'Herlihy (Douglas), David Conway (Portmarnock), Mike Hennessy (Lahinch), Rory Timlin (Galway), Eddie Condren (Bray)
80 Barry O'Leary (Greystones), David Walpole (Milltown), Dermot Morris (Limerick), Philip Clifford (Limerick), Don Weekes (Dunmurry)
81 Kieran O'Mahony (Galway), John Mullen (Co. Louth), Turlough Considine (Clontarf), Patrick Higgins (Forrest Little.), Tom Tyrrell (The Heath), Marcus Conroy (Galway), Martin Higgins (Claremorris)
82 Peter Cowley (Cork), Alan Mullen (Laytown & Bettystown), Pat Morrissey (Balbriggan), Brendan O Malley (The Royal Dublin), George Mellerick (Fota Island)
83 Joe Crowley (Athy), Des Egan (Loughrea), Denis Deasy (Waterford), Pat Lyons (Cork), Declan Corcoran (Thurles), Paddy Lewis (Woodbrook), Dom Fitzpatrick (Moate), Gerry Reeves (Limerick)
84 Gerard O'Donovan (The Royal Dublin), Philip Fulham (Glenlo Abbey), Kevin Knightly (The Royal Dublin), John Carroll (Bandon), Adrian Sheedy (Cork), Tony Hayes (Hermitage), Michael Byrne (Royal Jersey), John Corridan (Ballybunion), John Noonan (Grange), Anders Falk (Parknasilla), Jan Gilbert (Malone), Brendan A Barry (Gog Magog), Brian O'Connor (Hermitage)
85 David McHugh (Douglas), Patrick Doyle (Birr), Gerard Maher (Castletroy), Neville Atkinson (Woodbrook), Paddy Harrington (Muskerry), John Houlihan (Dooks), Ian Smyth (Clandeboye)
86 Brian McClean (The Royal Dublin), Patrick Hanrahan (Lindrick), Mick Heron (Gog Magog), Jack Maguire (Co. Louth), Dan Murphy (Youghal), Steve Prendergast (The Royal Dublin)
87 Denis Melia (Galway), Patrick J Murphy (Cork), Patrick Smyth (Killiney), Jack Dempsey (Curragh), Declan Sweeney (Rathfarnham), Tom Saunders (Ennis)
88 Gerald O'Keane (Gog Magog), Gerard O'Kennedy (Athlone), Justin Coughlin (Donegal), Ray Collins (Malone), Liam Horgan (The Heath), Patrick Comerford (Corrstown), Larry Cushen (The Heath), Tony Goode (Lucan), Paul Cooley (Portstewart), Brian Whitaker (Elm Park), Sean Duffy (Westmanstown), Paudie O'Callaghan (Mallow), Alistair Campbell (Massereene)
89 Michael Darcy (Oughterard), Tom Byrne (Greystones), John Waters (Portugal), Michael F Galvin (Limerick)
90 Richard Cotter (Delgany), William J O Brien (Ballykisteen)
91 Frank Leonard (Knightsbrook), John Cuffe (Monkstown), Michael Foley (Faithlegg), Paddy Donnachie (Cobh), Keith Lapsley (Dunfanaghy), Rory Fitzgerald (Tramore), Frank Cronin (Muskerry)
92 G. A. Finn (Cork), Paul Hautz (Delgany), Tim Hickey (Charleville), D E Chapman (Ballybunion), Niall Finnegan (Gort)
93 Kevin Murray (Tramore), William Mernagh (Kanturk)
94 Tim Griffin (Corballis Links)
NR Roy Hanna Jnr (Lurgan) NR.