New York, Aug 31 (IANS): Six-time champion Serena Williams registered a decisive win over Karolina Muchova from Czech Republic to enter the pre-quarterfinals of the ongoing US Open.

Williams defeated Muchova 6-3 6-2 after converting five of nine break points against the Wimbledon quarter-finalist.

The No. 8 seed American was broken back midway through the second set, but it was an otherwise flawless display from the 37-year-old in Arthur Ashe Stadium.

During her on-court interview after the match, Williams characterised her play as "intense."

She will now face Petra Martic, the No. 22 seed from Croatia for a place in the quarterfinals.

Martic defeated Anastasija Sevastova from Latvia 6-4, 6-3 to move to the fourth round.

Second seed Ashleigh Barty also entered the Round of 16 after securing a comfortable 7-5, 6-3 win over Greek 30th seed Maria Sakkari.

And third seed Karolina Pliskova overcame a mid-match blip to beat Tunisia's Ons Jabeur 6-1, 4-6, 6-4.