Momentum swung back and forth in the opening set between Watson and Saville, with the Briton rallying to a 4-2 lead after initially going a break down, only for Saville to level up.
Watson battled back from 40-0 down on serve to move within one game from the opening set, but she was unable to take her first set point.
A tie-break was confirmed by another exchange of breaks – but not before Watson initially refused to continue the match after being given a second time violation by the chair umpire.
She claimed she had been waiting for a ball to be returned to her, rather than deliberately delaying the point, but the umpire disagreed.
Saville ultimately stepped in and asked the umpire to give Watson her first serve back.
The Australian former world number 20 then dominated the tie-break and carried that momentum into the second set, quickly establishing a 3-0 lead.
Watson briefly threatened a comeback when she broke back for 3-2, but Saville was able to reset and closed out victory with another three-game streak.
