Serena Williams defeated Nuria Parrizas Diaz 6–3, 6–4 in the first round of the Toronto Masters 1000 on hard court. As the clear pre-match favourite with odds of 1.35, Williams delivered an expected victory against the Spanish qualifier, who entered at 3.38. The American controlled both sets with relative comfort, breaking Parrizas Diaz's serve multiple times to secure the straightforward two-set win. The result underlined Williams's continued competitiveness in the lead-up to the US Open, her home Grand Slam, where she would later announce her retirement from professional tennis.