The 23-year-old 'Bachelor' standout isn't afraid to get 'petty' after Luyendyk brutally blindsided Becca Kufrin on Monday's finale.
Bekah Martinez is putting Arie Luyendyk Jr. on blast.
The 36-year-old race car driver is feeling the heat after his Bachelor finale on Monday night, in which he proposed to Becca Kufrin, only to blindside her by ending their engagement weeks later (in an uncomfortable unedited hour of television) -- all in an effort to get back with his runner-up, Lauren Burnham.
The women of Luyendyk's season told ET at the Women Tell All taping that they were "heartbroken" over how he handled the finale -- and now they're unleashing all they've got against him!
Martinez, who was at Monday's taping, took to Instagram later that night to call out Luyendyk for sending her a direct message last month.
"DM’ing your ex on twitter is a great look too, no?" she wrote alongside screenshots of Luyendyk's messages. "#teampetty #teambecca."
Among the messages was Luyendyk poking fun at Martinez being on a missing person's list last month, sharing a photo of her Bachelor headshot on a milk carton. "This may just win the internet today. Such a shame they didn't use your license photo ?," he wrote.
The message was followed up by one a day later with a throwback pic of Luyendyk at a school dance, with two women on his arm. "Just realized you were born the same year as my first 2-on-1 ?," he wrote.
Martinez also threw shade at Luyendyk with another Instagram post reading, "That moment when you realize you dodged a bullet."
During an exclusive interview with ET last week, Martinez opened up about what she knew of Luyendyk's season finale and claimed that despite what he thinks, he's not ready for marriage.
"No, [I don't think he's ready]. I think I'm more ready for marriage than Arie is, quite honestly," she insisted. "I don't think Arie knows what he wants, and I don't think he's serious about being with one person for the rest of his life."
"I think Arie has a conflict between how he wants to present himself, and what kind of woman he thinks he should be with, and what kind of woman he knows he should be with, and then what he really wants," Martinez expressed. "I mean, you don't just change dating patterns you had for years and years at the drop of a hat because you're on a TV show -- that just doesn't change overnight."
See more in the video below.