Singapore - Wimbledon champion Garbine Muguruza served warning of her intention to win both the WTA Finals and the year-end world number one crown when she crushed Jelena Ostapenko in straight sets on Sunday.
The freshly crowned WTA player of the year was far too solid for an erratic Ostapenko, winning 6-3, 6-4 in 85 minutes to open her campaign in Singapore.
Muguruza, who was number one for four weeks until she was replaced by Simona Halep earlier this month, is one of seven players who can finish the year on top of the rankings if they lift the season-ending trophy.
In their opening match of the White Group round robin, the two power-hitters traded blows on the baseline with five breaks of serve highlighting a frenetic first set.
Muguruza enjoyed three of the breaks and benefited from the inconsistency of Ostapenko, the French Open winner who struggled with her first serve and gifted three double faults.
Ostapenko's high-voltage game was spectacular at times, as shown by her 16 winners in the first set. But 10 unforced errors sabotaged her chances against a ruthless opponent.
And the Latvian seventh seed's confidence appeared dented as she was broken early in the second set.
Muguruza, who is playing her third consecutive WTA Finals and was a semi-finalist in 2015, gained in strength to take control of the match.
The Spaniard started dictating on serve as the match wore on and continued to take advantage with her return in an impressive all-round performance.
The 24-year-old stuttered at the finishing line when she was broken when serving for the match. But she regrouped to eventually serve it out in the 10th game.
Earlier in White Group, in the tournament's opening match, Karolina Pliskova made an explosive start when she beat 37-year-old Venus Williams 6-2, 6-2 in 73 minutes.