One of his earliest successes was at the 1963 Dunlop South African Masters where he finished joint runner-up, three behind Bruce Keyter.

In February 1970, Westbrook finished runner-up at the South African Open, the nation's most prestigious tournament, three behind England's Tommy Horton.

[4] In January 1971, at the beginning of the 1970–71 season, Westbrook started the final round of the Natal Open tied with fellow South Africa golfers Bobby Cole and Simon Hobday.

He won his first four matches of the event then defeated compatriot Hugh Baiocchi on the 20th hole of the quarterfinals[10] and Scottish club professional Alistair Thomson in the semi-final.

[1] Two years after defeating Peter Oosterhuis in South Africa, he would compete against the English star again in the final round.