Svetlana Kuznetsova showed remarkable stamina to beat defending champion Agnieszka Radwanska in the WTA Finals just two days after qualifying for the season-ending tournament in Singapore.
Kuznetsova only sealed the eighth and final place in the lucrative event by winning the Kremlin Open on Saturday and carried on where she left off from Moscow by defeating third seed Radwanska 7-5 1-6 7-5.
The world number nine from Russia fought back from 4-2 down in the second set and saved a match point before winning a topsy-turvy first match in the White Group on Monday and has now come out on top in 13 of her 17 matches against the Pole.
Kuznetsova has had such a hectic schedule that she has seemingly not had time to fit in a haircut, as she chopped off her locks at a changeover in the second set during a match which swung this way and then the other.
Radwanska, ranked third in the world, was rewarded for a positive start when she opened up a 4-1 lead, but a spirited Kuznetsova came roaring back with a combination of rasping forehands and deft drop shots to take the opening set.
The favourite responded on Stadium Court, working Kuznetsova one way and then the other and breaking three times to level the match in quick time.
Kuznetsova, who has never passed beyond the round-robin stage of this competition, made 50 unforced errors but hung in there after being up against it time and again in the decider, saving a match point before breaking for a seventh time to end a gripping two-hour 48 minute contest.
Kuznetsova  bt Radwanska  7-5 1-6 7-5
Kuznetsova - 34/50
Radwanska - 29/32
Kuznetsova - 3
Radwanska - 5
BREAK POINTS WON
Kuznetsova - 7/16
Radwanska - 7/12
FIRST SERVE PERCENTAGE
Kuznetsova - 68
Radwanska - 66
PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Kuznetsova - 55/46
Radwanska - 56/47
Kuznetsova - 104
Radwanska - 108