Pliskova to set up double set point.
Following a Williams crosscourt forehand, Pliskova netted a down the line forehand to end the set.
Williams took a 2-1 set two lead before Pliskova held serve to level the set at 2 all.
Then after leading 40-15 on her serve, Williams struck two consecutive down the line forehand errors to drop serve and trail 2-3.
Pliskova held serve to lead 4-2 before Williams took the next three games to lead 5-4. The set then continued to remain on serve to reach a tiebreaker.
Williams struck a powerful forehand down the line winner to lead one point to none.
Pliskova then hit two down the line forehands winners of her own to lead 2-1 before she struck a down the line backhand volley winner to lead 3-1.
Pliskova increased her lead to 4-2 before Williams struck two groundstroke winners to pull even al 4 all.
The American double-faulted to trail 4-5 before Pliskova struck a down the line forehand wide after breaking a string in her racket to level the tiebreak score at 5 all.
The Czech hit a down the line forehand winner to reach setpoint at 6-5; only to send an inside out crosscourt forehand wide to reach 6 all.
Williams then set up match point with a down the line forehand winner.
A Williams crosscourt forehand passing shot winner would end the match after two hours and three minutes of play.
Following several weeks of improved results, on Monday Williams will move from 11 to 7 in the WTA Tour Singles Rankings.