However with Williams serving down breakpoint, Strycova returned the American’s powerful down the tee serve while standing many feet behind the baseline before counterpunching several powerful Williams forehands which perhaps pressured the American into sending a crosscourt forehand volley long to drop serve and trail 3-4.

Strycova held serve to lead 5-3 following four Williams baseline errors.

Serving to stay in the set, two Williams backhand errors followed by a forehand down the line hit long on set point leveled the match at one set all.

The American broke serve to start the final set before double faulting on breakpoint to lose serve to level the set at 1 all.

Hitting harder from the baseline than earlier in the match, Williams pulled ahead to a 4-2 lead after holding serve with a forehand down the line winner.

Strycova held serve to reach 4-3.

In the following game, Williams challenged a Strycova baseline shot after her own forehand landed long which held to the Czech player to say loudly to the chair umpire among other comments “it’s not right to wait after.”

Strycova’s ball was seen as long following a video review.

These comments from Strycova resulted in her being given a code violation from the chair umpire.

Both players held serve to put the score as 5-4 with the American still holding the lead.

With the Czech running down several extra balls, Williams committed several errors to trail 15-40 on her serve.

Strycova broke serve to level the match at 5 games all following a Williams backhand down the line hit wide.

Three forehand errors from the American sent the Czech ahead 6-5 as Strycova held serve.

Serving to stay in the match, Williams netted a backhand down the line in her 50th unforced error of the night to face matchpoint.

However the Czech sent a crosscourt backhand long as Williams reached deuce before holding serve to enter the tiebreaker.

Two groundstroke errors from Williams send the Czech ahead 2-0 before several powerful groundstrokes from the American leveled the tiebreaker at 2 all.

On the next point, Williams challenged a Strycova serve which was called out following a video review, which led to the Czech to complain “you wait too late to challenge.”

Strycova hit a forehand long following a second serve then continued to complain to the chair umpire after the point.

A forehand drop shot winner from the Czech leveled the tiebreaker at 3 all.

However two down the line groundstroke winners from Williams then sent the American ahead 5-3.

On the run, Williams hit a crosscourt backhand long to fall to 5-4.

The American hit a powerful serve down the tee which led to a crosscourt forehand return hit wide from the Czech which set up match point.

Williams netted a crosscourt backhand then screamed as the score reached 6-5.

Strycova hit a crosscourt forehand wide to end a powerful baseline rally and a match which lasted two hours and 54 minutes.

As the two players shook hands at the net, Strycova gave Williams a glare in possible disapproval of Williams’ challenges late in the final set.

Williams not amused, asked “What’s that look for? Was that look for something?”

Strycova replied, “Well done?” to which Williams answered “Okay, good.”

Thursday in the quarterfinals, Williams takes on the fourth seeded Agnieszka Radwanska of Poland at 3:30pm Doha time.