President Donald Trump responded to criticism from Senator-elect Mitt Romney on Wednesday, suggesting that now is the time for Republicans to work together on the nation’s issues as a “team” instead of fighting over style differences.

“Here we go with Mitt Romney, but so fast!” Trump marveled after Romney published a critical op-ed against Trump in the Washington Post.

Romney, who was elected last year to replace Orrin Hatch as U.S. Senator for Utah, lamented that Trump’s presidency made a “deep descent” in December, alleging that he “has not risen to the mantle of the office.”

Trump did not completely savage Romney, giving him a chance to work with him in Washington, but questioned whether he would end up like former Sen. Jeff Flake (R-AZ).

“Question will be, is he a Flake?” Trump asked. “I hope not. Would much prefer that Mitt focus on Border Security and so many other things where he can be helpful.”

Trump reminded Romney that the former Massachusetts governor lost his presidential election in 2012.

“I won big, and he didn’t. He should be happy for all Republicans,” he wrote. “Be a TEAM player & WIN!”