The world's biggest online shopping event raked in more than $30.8bn (210bn yuan; £23bn) in sales in 16.5 hours of trading, surpassing last year's all-time-high.
A gala featuring pop star Taylor Swift launched the 24-hour shopping blitz.
It marked Alibaba's first Singles' Day since the exit of its colourful founder, Jack Ma.
He was replaced as executive chairman by Daniel Zhang earlier this year after stepping down to focus on philanthropy and education.
The firm said sales reached $1bn in a little over one minute of trading on Singles' Day.
"Based upon that first hour... I would be really surprised to not see it come in above $32bn," said Daniel Newman, technology analyst at Futurum Research.
The shopping festival began in 2009 with participation from just 27 merchants as an event to raise awareness about the value of online shopping. More than 200,000 brands are participating in this year's event.
The number of delivery orders also exceeded one billion after 16 hours, beating the total number of orders in 2018.