The last decade
It’s imposing enough that in the last decade, no threesome of major champions has made much of a run at it. The closest any trio has come was in 2015.
The stars that season were Jordan Spieth, Jason Day, and Bubba Watson. Spieth was at his peak, a five-time champion on Tour whose victories included his first two Majors, the Masters, and U.S. Open, along with the Tour Championship. At 68.938, he led the Tour in stroke average, that figure working out to a .972 Relative Stroke Average against the Tour norm of 70.95.
Day wasn’t far behind Spieth. A four-time winner on Tour, he made the 2015 PGA his first – and to date only – Major title. Day also won the Canadian, the Barclays, and the BMW, the latter two both part of the Tour Championship Series. His 69.161 stroke average, second only to Spieth, worked out to a Relative Stroke Average of .975.
Watson did not win a Major in 2015, but by then he already had a pair of Masters green jackets to establish his worthiness to be considered among the game’s top tier of players. His 69.296 stroke average for the season ranked third behind Spieth and Day, and translated to a Relative Stroke Average of .977.
That averages out to a Relative Stroke Average of .975 for the 2015 Triumvirate. It’s an excellent average, although slightly higher than the .972 attained to date by Rahm, Scheffler, and McIlroy.