The Red Sox rightfielder hit for the cycle on Thursday night, capping off the feat with a home run in the top of the ninth inning. He singled and scored in the first inning, tripled in the second and doubled in the fourth against starter Ryan Borucki.
The rightfielder becomes the first Red Sox player to hit for the cycle in a loss since Carl Yastrzemski in 1965, according to ESPN Stats & Info.
"I don't know if you can [stop Betts from hitting], especially because he's hot", Blue Jays manager John Gibbons said of Betts.
Justin Smoak picked up a double and two singles to record back-to-back three-hit games.
Borucki gave up a solo home run to J.D. Martinez in the fourth, his homer less streak coming to an end at 47.1 innings, tied for the third longest all time by a Blue Jay to start their career.
Eduardo Nunez helped the Red Sox open the scoring in the first inning. Porcello lost for the first time since a July 13 home defeat to the Blue Jays, a game in which he allowed a season-worst eight earned runs. Grichuk hit his two-run dinger in the fifth for his 16th.
"I'm trying to be competitive and have good at-bats", Smoak said of his streak. "The last few weeks have just felt pretty good".
Boston's Brock Holt is caught stealing second as Toronto's Aledmys Diaz stretches to make the tag in the fifth inning.
The Blue Jays added to their lead in the third. Martinez now has MLB-leading 35 round-trippers.
He made his major league debut on June 26th against the Houston Astros and distinguished himself despite a 7-0 setback to the defending World Series champs, surrendering just two of the runs off six hits over six innings of work. But it wasn't until the ninth that Betts pulled off his first career cycle with a home run over the left-field wall at Rogers Centre off Toronto's new closer, Ken Giles. "It sucks that I did it in a loss but turn the page and get ready for tomorrow".