10 -- Tom Seaver (NYM)
April 22, 1970, vs. Padres
The Mets led the Padres 2-1 behind an already strong outing from Seaver in the top of the sixth, when the righty struck out Al Ferrara to end the inning. Seaver would go on to complete the game and he recorded each of the final 10 outs via strikeout beginning with Ferrara. Seaver finished the game with another strikeout of Ferrara to seal the Mets' 2-1 win. It was Seaver’s 19th strikeout overall, marking his career best. At the time, he was the first pitcher to strike out 19 batters in a nine-inning outing, though four pitchers have since racked up 20.