Diaz went 2-for-5 with a solo walk-off home run and an additional run in Monday's 5-4 win against the Red Sox.
Diaz broke a 4-4 tie and sent the Astros home with a win on a 401-foot shot off Kenley Jansen in the ninth inning. It was the second straight game with a long ball for Diaz, who has gone deep four times in his past 10 contests. Diaz had just 10 homers across 103 games prior to the recent power surge.