The German, victorious at the Australian Open and US Open this year, took control of the tie against Romania’s Halep in the opening set.

After taking the first 6-4, Kerber refused to let her opponent back into the match and quickly wrapped up a straight sets 6-4, 6-2 triumph.

Having battled from a set down against Dominika Cibulkova in her opening match of the tournament to win, Kerber lies top of the Red Group standings.

The 28-year-old, who has never progressed past the group stage of the event for the top eight available female players in the world rankings, looks almost certain to seal one of the two semi-final places on offer.

Madison Keys will take on Kerber next, with the American having boosted her hopes of advancing by securing her first win of the tournament.

Keys, who was beaten by Halep in her opening match, claimed the first set 6-1 against Slovakia’s Cibulkova.

Despite a closer second set, Keys would have too much for her rival to win 6-1, 6-4 and move up to second in the standings.

Should Keys beat Kerber in straight sets in her final group match, she would be guaranteed a place in the semi-finals.

Kerber only requires one set from the tie to secure her place in the final four, while she would also be assured of a spot if Halep fails to beat Cibulkova in straight sets.

Tomorrow will see the White Group return to the court, with defending champion Agnieszka Radwanska of Poland and Spain’s Garbine Muguruza both hoping to secure their first win.

One of Russia’s Svetlana Kuznetsova and the Czech Republic’s Karolina Pliskova will take a major step towards the semi-finals by earning their second victory of the tournament, when they go head-to-head.