That will be both a primary focus of the Edmonton Eskimos on Sunday and also their biggest challenge in their attempt to beat the Calgary Stampeders in the CFL West final and earn a berth in the Grey Cup.
The Stampeders running back led the league in rushing with 1,082 yards while playing just nine games. Two of those games were against the Eskimos and he ran for 272 yards in back-to-back Calgary victories in September.
"We want to stop him because their offence does evolve around him most of the time," Edmonton's six-foot-six, 234-pound defensive end Willie Jefferson said after the team's closed practice Thursday.
"We have to slow him down, make them try to find another way to win the game without him."
But, he admitted, a "lot of things are easier said than done" and the Eskimos defence has to do a better job of tackling Cornish then they did in the previous two games.
Edmonton head coach Chris Jones — a former Calgary assistant — said stopping Cornish begins with his players staying in their proper gaps and lending support.
"He gets his pads turned north and south and we have to make sure, once he gets turned north and south you have to get a hand on him and get some help," Jones said. "He's a big back; he's going to break tackles so we have to do a great job of getting a lot of people there."
The Eskimos lost all three games to Calgary this season. In their back-to-back Labour Day losses Edmonton was without quarterback Mike Reilly and, as of Thursday, Jones wasn't prepared to declare him the starter.
Reilly missed the final regular-season game with a foot injury and came on in the second half of Edmonton's 18-10 semifinal win over Saskatchewan last weekend.
Jones said he "looked awfully good today."
Linebacker Dexter McCoil, the West's outstanding rookie, missed Thursday's practice to attend to a family matter but Jones said he was expected back in time for Friday's practice.
While Cornish is a focus of the Edmonton defence, the Eskimos are confident their running back, John White, will match Cornish on Sunday.
"Best running back in the league," said Jefferson. "Quick feet, likes to be aggressive, when our offence is on the field all eyes are on him."
White, who also played only nine games, finished third in rushing with 852 yards but was second to Cornish (7.8 yards) in yards per rush at 6.9. Edmonton finished second to Calgary in rushing yards per game (143.9 to 129.4) but ahead of them in total offence per game (382.6 yards to 378.9).
"He's a tremendous blocker, both in the pocket and outside the pocket," Jones said of White who ran for 134 yards against the Roughriders. "He's very hard to tackle, he's elusive, he breaks a lot of tackles and he's a lot stronger than you think he is."