Answered April 1st, 2019

David Thompson scores 73 points (the most ever by a guard at the time) but loses the scoring title to George Gervin who later that same night dropped 63 to edge him out 27.22 PPG to 27.15 PPG in the closest scoring race ever.

Who was the first guard with 70 points in a game?
Interpreted as:
Who was the first guard with 70 or more points in a game?