Lu/Mitrofanov placed 5th at both of their JGP assignments. In January, they won the junior pairs' title at the 2018 U.S. Championships; they ranked first in both segments and outscored the silver medalists by 17.74 points. In March, the pair placed 5th (6th in the short program, 4th in the free skate) at the 2018 World Junior Championships in Sofia, Bulgaria.