Sinner recovered from early difficulties to beat Christopher O’Connell 6-4 6-3 to reach the quarter-finals.
Wales lost 5-4 on penalties to Poland after a goalless 120 minutes in Cardiff.
Maia Bouchier defied injury to hit 91 as England Women outpowered New Zealand to win the fourth T20 international in Wellington by 47 runs and clinch the series.