Diaz worked around a pair of base hits to deliver a scoreless inning and claim his league-leading 42nd save of the season in Monday's 4-3 win over the Rangers.
Diaz wasn't quite as dominant as usual while allowing singles to two of the first three batters he faced, but he got Willie Calhoun to foul out and struck out Shin-Soo Choo swinging to strand the tying run at second base. With a 14.9 K/9, 1.96 ERA, 0.80 WHIP and a nine-save gap between him and any other MLB reliever, Diaz has unquestionably been the most valuable fantasy closer this season, a surprising development after an occasionally bumpy 2017 campaign.