That enabled the Lions to finally pick up a win in the hard-fought, four Test series and add a Test win to their unbeaten record in the provincial games.
"Colm was a really nice guy and was a top tourist. We didn't know too much about him before the tour because he had only played three times for Ireland," said Beaumont.
"He came in from the outside, but he turned into a great team player. He had to wait for his chance to get into the Test team, but he played consistently well and then started in the final two tests.
"We got very close to wining the third Test and then had to win the final game to stop the Springboks completing a whitewash. Before the game I recall telling the players we didn't want to be remembered like the 1966 Lions, who lost all four Tests in New Zealand.
"We felt we'd been unlucky in two of the three previous Tests and were determined to end on a high note. Colm played his part to the full in our win. That game remains among the highlights of my career.
"Colm was still a young man and it was a great shame to hear of his death. The thoughts and condolences of everyone who toured with him in 1980 go out to his wife and family."