Ulster surprised Leinster by winning all four foursomes and then went on to win by 7 1/2 to 5 1/2 in the opening round of the three-day amateur interprovincial golf championship at a windy Ballybunion yesterday. Munster, the holders, who have won the event four times in five years, beat Connacht by 111/2 to 11/2 matches.

Ulster had 6 1/2 points up out of 12 with the final singles match in progress and everything looked certain when Colin McElderry was two up with four to play on Michael McGinley. However, he duffed his drive at the 17th and the Leinster man had to concede the 18th when he was in the rough from his drive and completely missed his second.

Munster were too strong for Connacht, whose only winner was young Mel Flanagan who beat Karl Bornemann by 2 and 1. In the last match of the singles the young teenager Sean McTernan got a half with the very experienced Tom Cleary.