Hamilton's winning drive started with under two minutes on the clock and the ball well inside the Eskimos' half of the field.
Cobb, the two-time league player-of-the-week in his first campaign north of the border, had been held in check nicely by the Eskimos all night and this time was able to get just three yards on a first-down handoff from Porter.
Already in field goal range for Nick Setta, the Cats gave the ball to the diminutive Michigan State product again, hoping he could get a couple of yards up the middle and keep in good position for the kick.
But Cobb bounced off the big fellas plugging the line, deked to his right and found some open field. Out-running three Edmonton defenders, he seemed to make it into the end zone but replays put the ball just over a yard out.
Porter ran it in from there on a nice second effort for the winning score.
A late drive by the Eskimos fell short as time ran out.