At Fastlane, Mysterio failed to capture the United States Championship, where Samoa Joe retained in a fatal four-way match also involving R-Truth and Andrade. On the March 12 episode of "SmackDown Live", Mysterio pinned Samoe Joe in a tag team match, which led to Mysterio earning a United States Championship opportunity. At WrestleMania 35, he was defeated by Joe. On April 15, as part of the Superstar Shake-up, Mysterio was drafted to the Raw brand. At Money in the Bank, Mysterio defeated Joe to win the United States Championship for the first time, becoming the twenty-first WWE Grand Slam Champion in the process. On the June 3 episode of "Raw", Mysterio announced that he would vacate the title the week after due to suffering an injury from a post-match beatdown by Joe. Mysterio returned from injury on the July 8 episode of "Raw", where he was defeated by Bobby Lashley. In August, Mysterio teased his retirement due to multiple losses and amounting injuries, with his son, Dominik, trying to persuade him to not give up.