The attacker broke Abby Wambach's record when she scored her 185th goal for Canada in the 23rd minute of an 11-0 win over Saint Kitts and Nevis in Olympic Games qualifying.
Sinclair, 36, earlier opened the scoring with a seventh-minute penalty in her 290th international appearance.
United States legend Wambach - who netted her 184th goal in 2015 - held the record for over six years after surpassing compatriot Mia Hamm's 158 goals in June 2013.
"I definitely feel a relief," Sinclair, an international since 2000, told Canada Soccer.
