Victoria Azarenka's return to major tennis will be given its sternest examination yet after she booked a Wimbledon round-of-16 meeting with world number two Simona Halep.

Serena Williams and Maria Sharapova's absences, added to early eliminations for Petra Kvitova and Karolina Pliskova, have blown the women's singles draw wide open.

The progression of Azarenka in her first grand-slam appearance since the birth of her first child has been impressive thus far and the Belarussian came out on top after a rollercoaster return to Centre Court on Friday, beating home favourite Heather Watson 3-6 6-1 6-4.

The deciding set was a particularly fraught affair as momentum swung between the two, but Azarenka held her nerve when serving for the match after a string of breaks had left the crowd on the edge of their seats.

Halep's place in the second week appeared more comfortable on paper, but the Romanian second seed was made to work hard for a 6-4 7-6 (9-7) win over Peng Shuai.

The French Open finalist - stunned by Jelena Ostapenko in Paris - used her superior power to put Peng on the back foot, but familiar cracks in the Romanian's mentality threatened to arise in the second set, while a pedestrian second serve was a regular source of joy for the Chinese.

Ultimately, though, Halep proved too good and she will hope for a repeat performance of her US Open quarter-final over Azarenka in 2015 as she plots a course to a third SW19 quarter-final and the top-ranking against a former world number one.