Venus Williams has secured herself a place in the semi-finals of the WTA Finals in Singapore with a 7-5 6-4 win over Wimbledon champion Garbine Muguruza.

The 37-year-old veteran joins Karolina Pliskova and Caroline Wozniacki in the final four, while Muguruza is eliminated from the tournament.

The last spot will be decided on Friday after the results of the final Red Group matches are known.

The first set was an absorbing encounter, with no breaks to start with, although both players had plenty of opportunities.

When Muguruza finally did take advantage to gain a 4-3 lead, Williams broke right back.

She then held on to narrowly take the first set, and the second was just as close.

However, Williams always seemed in control, and the 37-year-old is a sentimental favourite heading into the semi-finals.

It was Williams’ second tight match in a row, although at 1 hour 41 minutes it wasn’t as long as her victory over Jelena Ostapenko on Tuesday, which over three hours.

In the day’s earlier singles match, Ostapenko dispatched Pliskova 6-3 6-1 in 66 minutes.

It doesn’t make any difference to the Red Group however, after the French Open champion lost her first two matches.

The doubles also got underway on Thursday, with Hungary’s Timea Babos and Andrea Hlavackova from the Czech Republic beating Andreja Klepac from Slovenia and Maria Jose Martinez Sanchez of Spain 6-3 6-4.

Martina Hingis from Switzerland and Yung-Jan Chan of Chinese Taipei will play against the Czech Republic’s Kvete Peschke and Germany’s Anna-Lena Groenefeld in the late doubles match.