Tramore’s Robin Dawson got off a magnificent start in the Cape Province Open Championship when he fired seven birdies in a six under par 66 to lie just a shot off the lead.
Just a few days after finishing second in the South African Open Strokeplay at the same venue, the Maynooth University star birdied five holes in a row from the third at Kingswood Golf Estate, then added two more at the ninth and 10th to get to seven under par.
A bogey at the 17th left him tied second on six under par with South Africa's Brandon Cloete, just one stroke adrift of Paul Margolis of France, who made nine birdies in a seven-under par 65 at George Golf Club, the other course hosting the event.
Castle and UCD's Alex Gleeson, who was 11th in the South African Open Strokeplay, continued his fine start to the season by making five birdies in a three-under 69 at Kingswood, where all eight Irish entrants began the championship.
Kevin Le Blanc from The Island and Maynooth is tied 14th after a 70 where he followed birdies at the third and fifth with an eagle at the par-five seventh before dropping two shots coming home.
Le Blanc's Maynooth University teammate Stuart Grehan from Tullamore is tied 30th after an up and down 72 that had a little of everything.
While he made three birdie twos and an eagle three at the seventh, the former East and South of Ireland champion also made three bogeys and a double bogey six.
With the cut for the top 65 and ties set to fall after Wednesday's second round, Whitehead's John Ross Galbraith (75, T95), Naas' Conor O’Rourke (76, T85), Warrenpoint's Colm Campbell (77, T95) and Knock's Colin Fairweather (79, T117) have work to do to qualify for the final two rounds at Kingswood on Thursday.
SANLAM Cape Province Open Championship, Kingswood Golf Estate and George Golf Club
65 Paul Margolis (France)
66 Brandon Cloete (South Africa), Robin Dawson (Ireland)
67 Jeremy Freiburghaus (Switzerland)
68 Victor Veyret (France), Herman Loubser (South Africa), Robin Williams (England)
69 Alex Gleeson (Ireland), Richard Joubert (South Africa), Wilco Nienaber (South Africa), Barend Botha (South Africa), Loris Schuepbach (Switzerland), Craig Ross (Scotland)
70 Marco Steyn (South Africa), Malcolm Mitchell (South Africa), Luke Jerling (South Africa), Martin Vorster (South Africa), Kevin Le Blanc (Ireland), David Mcintyre (South Africa), Alex van Wyk (South Africa)
72 Stuart Grehan (Ireland)
75 John Ross Galbraith (Ireland)
76 Conor O’Rourke (Ireland)
77 Colm Campbell (Ireland)
79 Colin Fairweather (Ireland)