Six minutes into the second quarter, Cowboys linebacker Lee Roy Jordan tackled Unitas, causing him to fumble. Defensive lineman Jethro Pugh recovered the loose ball at the Baltimore 28 and Dallas capitalized three plays later, scoring on a 7-yard touchdown pass from Morton to Thomas to establish a 13-6 lead. The next time the Colts had the ball they quickly turned it over yet again, with Unitas unleashing a fluttering interception to Renfro while being hit fiercely on a pass. Unitas was knocked out of the game permanently on the play with a rib injury and was replaced by Earl Morrall, who was widely blamed for the Colts loss in Super Bowl III. The Cowboys, starting from their own 15, were unable to score any points off the turnover. After sustaining a 15-yard pass interference penalty, they punted. After regaining possession, the Colts offense, led by Morrall, stormed all the way to the Cowboys 2-yard line with less than two minutes remaining in the half. However, the Cowboys defense stiffened. Colts running back Norm Bulaich was stuffed on three consecutive rushing attempts from inside the 2-yard line. On fourth down, Morrall threw an incomplete pass, turning the ball over on downs and ending the half with Dallas leading 13–6.