Oscar Robertson's NBA record of 41 triple-doubles in a single season had stood for 55 years but Russell Westbrook changed that.
Oklahoma City Thunder guard Westbrook had 50 points with 10 assists and 16 rebounds in Sunday's 106-105 win over the Denver Nuggets, eclipsing Robertson.
The mark fell with Westbrook's 10th assist — a kick-out pass beyond the arc to Semaj Christon, who sank the three-point jumper.
Westbrook nearly broke the record in his last two games. He scored 45 points, 10 assists and nine rebounds in Wednesday's 103-100 win over the Memphis Grizzlies. His 10th assist of that game was a kick out to Doug McDermott for a three-pointer with 1:23 remaining in regulation to give the Thunder a 98-95 lead. He barely missed a pair of rebounds in the final minute, either of which would have given him the record.
He then came up two assists shy in Friday's 120-99 loss to the Phoenix Suns as the Thunder shot 36.6 percent from the floor and Westbrook was just six of 25.
Westbrook tied Robertson's hallowed record with 12 points, 13 rebounds and 13 assists in Tuesday's 110-79 win over the Milwaukee Bucks.
He is averaging 31.7 points, 10.4 assists and 10.7 rebounds per game and has clinched a triple-double average for the season with just two games remaining. He joins Robertson as the only players in NBA history to average a triple-double for an entire season.
During his second NBA season, Robertson averaged 30.8 points, without the benefit of a three-point line, to go with 12.5 rebounds and 11.4 assists per game for the Cincinnati Royals.
Westbrook, who is in his eighth season, now has 79 career triple-doubles to break a tie with Wilt Chamberlain for fourth-most all-time. He still has a ways to go to catch Robertson's career mark of 181. Next on the list is Jason Kidd, who had 107 career triple-doubles.
Robertson was a 12-time All-Star during his 14-year career and helped the Bucks win their only NBA championship in 1971.
The "Big O" was also the NBA's MVP in 1964 while still with the Royals.
Westbrook may not win the NBA's MVP award this year, but the six-time All-Star has had a season that will be immortalised in the record book and is the main reason the Thunder will be in the playoffs as the likely number six seed in the Western Conference.