Top seed Simona Halep was eliminated from the WTA Finals on Thursday as Agnieszka Radwanska kept her slim hopes of progression alive with a 7-6 (7-5) 6-1 victory over the Romanian in Singapore.

Radwanska came into her final Red Group match knowing only a straight-sets triumph, coupled with Maria Sharapova beating Flavia Pennetta by the same margin later in the day, would be enough to secure a place in the semi-finals.

And the Pole kept up her end of the bargain, ultimately recording her 500th career win with ease as Halep fell away badly after giving up a commanding lead in a first-set tie-break.

Having earlier saved two set points, Halep moved 5-1 up in the breaker, only to lose six points in succession.

An energised Radwanska then raced through set two, with Halep guilty of increasingly frequent errors as her participation in the event was brought to an end.

Sharapova is now guaranteed to be involved in the semi-finals, while Pennetta will join her at Radwanska's expense providing the US Open champion avoids a straight-sets defeat in her meeting with the Russian.

It was Halep who claimed the initial advantage against Radwanska, who was broken in the opening game despite getting all of her first serves in.

However, Radwanska's impressive court coverage gradually wore Halep down and the score was brought level at 3-3 when the latter's smash was miscued badly following a lob from her opponent.

Halep fought doggedly to save two set points in the 10th game and looked set to move ahead when Radwanska started the tie-break sloppily.

However, a wonderful backhand volley heralded the start of a fine recovery from the fifth seed and she converted her third set point when a sensational rally ended with Halep volleying wide.

The contest proved one-sided thereafter, Halep guilty of countless unforced errors as she slumped to defeat - winning just one point across her final three service games.