HAMILTON — On a night when he wasn't at his best, a Bo Levi Mitchell incompletion moved the Calgary Stampeders closer to clinching top spot in the West Division.

Rene Paredes' 17-yard field goal on the final play earned Calgary a hard-fought 28-25 win over a spirited Hamilton squad Friday night. Paredes' boot was possible thanks to a pass-interference call on defender Courtney Stephens following Mitchell's jump-ball throw to Anthony Parker that moved the Stamps 62 yards to the Tiger-Cats' 10-yard line.

"I'll be honest, I understand how to win a football game," Mitchell said. "P.I. is a very big thing, it's a very good weapon to use.

"Sure, I love to throw touchdowns but you've got to understand situation-wise if you don't get the ball there a completion is game over. I put the ball up high, let a guy come back to it and go jump for it and obviously let someone try run through him and get a penalty. It was a good job by Parker coming back to it but that's kind of how you draw it up there in the end."

Stephens made no excuses for the penalty.

"I let my team down," said the Brampton, Ont., native. "It's a 50-50 ball and you like to think the odds are in our favour but I didn't make the play.

"I'm not going to change the way I play, I'm still going to be aggressive and try to make plays. If it's really a 50-50 ball that means the next one I got it."

Mitchell, the CFL's outstanding player last season, was 19-of-34 passing for 279 yards with a TD and interception. The league's top-scoring offence (29.4 points per game) managed just 306 net yards against Hamilton, holding the ball for just 25 minutes 43 seconds.

"I'll go watch the film but it's more physical than mental," Mitchell said. "Just go out there and get the body right and go out there and have a better game."

Friday's contest was in stark contrast to the last time the two teams met when Calgary throttled Hamilton 60-1 at McMahon Stadium on July 29. However, that was with Kent Austin as Ticats head coach and Zach Collaros the starter.

Hamilton (4-11) fell to 4-3 under interim head coach June Jones, whose first decision was to make backup Jeremiah Masoli his starter. Masoli was 24-of-41 for 326 yards with an interception and rushed for 29 yards while Brandon Banks had 11 catches for 115 yards.

"Actually, I thought it was going to play out like this," said Calgary head coach Dave Dickenson. "I thought it was going to be a very very difficult game, I knew it would go 60 minutes.

"I know the desperation Hamilton was playing with, they have good players and they've been playing well. I felt it would come down, not necessarily to the last play, but right to the end and it did."

Paredes' field goal came after Hamilton's Alex Green scored on a one-yard run with 36 seconds remaining that Kenny Allen converted. It was set up by a pass interference call on Calgary's Jamar Wall that gave the Ticats the ball at the Stampeders' one-yard line, delighting the Tim Hortons Field gathering of 23,672.

Green's TD came after Mitchell hit Kamar Jorden with a 25-yard scoring strike. The two then combined on the two-point convert at 10:01 to put Calgary ahead 25-18.

Calgary (13-1-1) improved to 16-0 coming off the bye and earned its 11th straight victory. The Stampeders will cement the top spot in the West Division — and host the conference final — if the B.C. Lions beat the Winnipeg Blue Bombers on Saturday night.

Hamilton's loss clinched Toronto (7-8) a playoff berth and a home game. The Argos visit the Edmonton Eskimos (8-6) on Saturday.

Pouring salt in the wound, the Tiger-Cats were eliminated from the post-season after the Ottawa Redblacks beat the Saskatchewan Roughriders 33-32 later Friday night. Hamilton's elimination also means the fourth-place team in the West Division will cross over and become the third playoff seed in the East.

Allen's 28-yard field goal at 7:56 of the fourth gave Hamilton an 18-17 advantage after Paredes connected from 37 yards out at 3:25. Allen then booted a 27-yard field goal to put the Ticats ahead 15-14 after blowing a glorious scoring opportunity earlier in the quarter.

Don Unamba returned a Marquay McDaniel fumble 24 yards to the Calgary 22-yard line. Following an intentional grounding penalty, Masoli hit Luke Tasker on a 24-yard reception, setting up a third-and-one gamble.

But instead of lining up under centre and running the ball, Masoli was in shotgun and threw an incompletion to give Calgary the ball back at its four-yard line.

William Langlais had Calgary's other touchdown. Paredes booted a convert, single and four field goals.

Green finished with two TDs for Hamilton with Masoli scoring the other. Allen had a convert and two field goals.