Johnston scored a power-play goal on six shots and went minus-2 in Monday's 4-2 win over the Golden Knights in Game 4.
Johnston has three goals over the last two games to help the Stars bounce back from a 2-0 series deficit. His second-period tally Monday tied the game at 2-2. The 20-year-old has four points, 18 shots on net, four hits and a minus-1 rating through four playoff appearances. He's found instant success since a promotion to the top line, so he'll likely remain there for Wednesday's Game 5.