Morison's double against Stevenage took his tally to 30 for the season
Steve Morison scored twice as 10-man Stevenage took a firm grip of their Blue Square Premier play-off semi-final against Cambridge United.
Stevenage looked up against it when Darren Murphy was sent off for violent conduct on the stroke of half-time.
But Mark Roberts fired the home side ahead, only for Lee Phillips to volley Cambridge level within two minutes.
Morison rose above Josh Coulson to head Stevenage back in front, before adding a third as Cambridge poured forward.
Chances were at a premium in a competitive first half, although the best fell to the visitors as Phillips was narrowly wide with a fierce 25-yard drive and Danny Crow headed Jai Reason's cross wide from six yards.
The tie truly appeared to turn in Cambridge's favour in first-half stoppage time when Murphy was shown a straight red card by referee Rob Whitton, following a consultation with his assistant, after challenging Jon Challinor in the air at a Stevenage corner.
But the 10 men refused to lie down and were ahead within two minutes of the restart when Roberts prodded home from close range after Morison had headed Andy Drury's free-kick back across goal.
The lead was shortlived thanks to Phillips brilliantly firing home from the edge of the box after Crow had chested the ball into his path.
Stevenage were back in front on the hour when Morison beat Coulson to head in another Drury cross for his 29th goal of the season.
And after the visitors had had a penalty appeal waved away, Morison took his tally to 30 and gave his side a two-goal cushion to take to the Abbey Stadium in the second leg when he fired left-footed past U's keeper Danny Potter after more good work from Drury.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.