Maryland coach Ralph Friedgen has Merrills in the lineup with a little wish of his own. He is hoping for the runner to be like Chris Downs, or even Bruce Perry, the first featured backs he had from his first two teams at Byrd Stadium.
Perry came out of nowhere in Friedgen's first season to lead the Terps to the ACC title while becoming an All-American and league offensive player of the year. Downs came from deeper in obscurity to replace the injured Perry in 2002 and exploded on the scene with 1,154 yards on 208 carries - an average of only 15 per game - and 13 touchdowns.
Merrills, who is friends with Downs, only had 367 yards in 96 carries in his three-year career before Saturday. That might all change.
"If he keeps it up like he's done, he will be the running back," Friedgen said. "I was surprised that we even played him that much, because that wasn't the plan going in.
"He had eight or nine broken tackles in the game, and I don't think he had eight or nine broken tackles in the preseason."
What a difference game conditions make. Merrills' success became a rallying point for the Terps' offense in their final drives to come back from 14-9 and 20-15 deficits to win a showcase game for Maryland fans.
"Seeing Mario get 100 yards meant a lot to the offensive line," said center Ryan McDonald, a Williamsport graduate. "You just want to get at least 100 yards rushing as a team, and we are trying to establish the run more this year."
Merrills may have established more.
He ran for 10 yards on his first carry to get started. He accounted for 22 of the 66 yards on Maryland's first drive, resulting in a field goal. Merrills also scored on a 12-yard run to give the Terps a 15-14 lead and ran in the conversion with 1:01 remaining for the final points.
"I was trying to get them fired up in the huddle," Merrills said. "They could see the fire in my eyes and vice versa. At no point did we lose confidence. It was do-or-die time."
At the same time, the outing against Navy is a performance that might place Merrills in the lore of Maryland running backs, like Perry and Downs. Another starter out of nowhere could make a big name if Merrills duplicates his output Saturday against a much-quicker Clemson defense.
"When you are sitting back and watching (Perry and Downs), you know you are part of something special," he said. "I'm always compared to Downs. Bruce came out and made an impact. ... Hopefully, I can keep it going."
But for 30 carries?
"The bar is set high. ... I'm just looking to improve," he said.