Donald Trump fired back at Scott Walker on Tuesday after the Wisconsin governor endorsed his chief rival Ted Cruz.

"I wouldn't have done this,” Trump said, admitting the motive behind his attacks was based solely on Walker's decision to back the Texas senator. "When he endorsed Cruz, what am I gonna do, am I gonna say he's doing a great job? He's not doing a great job."

Trump says he never expected to get Walker’s endorsement, especially not after the way the two fought during Walker’s short time vying for the Republican nomination. Nonetheless, Trump used the opportunity to attack Walker for Wisconsin’s budget deficit and state debt.

Noting that he was reading his statistics from “books,” Trump said they “may be wrong” but they’re “very high” numbers. Walker, for his part, fact checked the New York real estate mogul in real time via Twitter.

In 2015, 36 states had worse unemployment rates than in 2007. 4 states were same. WI was 1 of just 10 with better rate. — Scott Walker (@ScottWalker) March 29, 2016

But it wasn’t just a number-based attack that Trump unleashed on Walker. He hit him for stealing Trump’s phrase of “common sense conservative” and that Walker gave him a plaque to thank him for a prior donation but Trump never really paid it much mind. In fact, he had a “girl” in his office find it, which she did “under a pile of a lot of other plaques.” Trump promised to try to bring it to Wisconsin this week.

Walker wasn’t the only governor who is gone from the race but not forgotten by Trump. While Walker’s endorsement of Cruz drew Trump’s ire, Jeb’s endorsement seemed to go unnoticed by Trump who asked the crowd “did Jeb endorse anybody?” The former Florida Governor endorsed Ted Cruz a week ago. “Shows you how important it is,” Trump scoffed. “No one even knows.”

Knowing he was in House Speaker Paul Ryan’s home town, Trump polled the crowd on how they felt about him – and was “surprised” to hear “boos” called back at him. “Wow,” Trump exclaimed. “I was told to be nice to Paul Ryan because — really?”