Johnston posted an assist in Monday's 4-3 loss to the Golden Knights in Game 1.
Johnston set up Jamie Benn's breakaway tally in the first period. Johnston had six points over 19 playoff outings a year ago, and he built on that experience with 32 goals and 33 helpers over 82 regular-season contests this year. The 20-year-old should continue to provide solid offense from a middle-six role.