Alcaraz has beaten Zverev twice in a row, but the German has been the better player in faster conditions.
As Williamson returns, one of the star performers in the historic series win over India, spinner Ajaz Patel, has been dropped.
Viktoria Hruncakova and Tereza Mihalikova completed the surprise victory, surviving a late rally by Taylor Townsend and Ashlyn Krueger.
Some results have been hidden because they may be inaccessible to you
Show inaccessible results
Feedback