Later on the first drive, Johnston once again made himself available to the Bolts quarterback in the end zone for the first points of game.
And his first of two touchdown grabs that proved to be the difference in the second multi-score game of his career.
"Just trusting coach's play calls, run them to the best of my abilities," Johnston said. "When Justin needs to throw the ball, always be available to be there for it."
The wide outs making themselves available all night proved to be a theme, including with the second-year receiver McConkey.
McConkey hauled in six receptions for 74 yards, working all over the field and getting open while lining up in both the slot and on the outside.
He picked up right where he left off from his rookie season.
"Our guys were getting separation and they were running good and catching the football," Harbaugh said. "It looked good, passing game looked good, that's a real strength for us and the guys executed it at a really high level tonight."
Johnston said: "It hypes us up. Day in and day out, whether it's in the game, practice or even the meetings. We're always bouncing ideas off each other, making ourselves better each and every day."
Speaking of picking up where they left off — a familiar face brought the whole performance together and helped push it over the finish line.
When it came down to it there was none other than Allen, kicking off his 12th campaign in powder blue and back like he never even left.
"Felt like home, back out there with the guys and Herbo," Allen said. "It was good."