quarter, pushing the Cowboys back to the 22-yard line and forcing them to settle for Clark's 30-yard field goal, stretching the score to 6–0. On their next possession the Colts offense got a break. After two straight incompletions to open the drive, Unitas uncorked a pass to Eddie Hinton that was both high and behind the receiver. The ball ricocheted off Hinton's hands, was tipped by Dallas defensive back Mel Renfro, then landed in the arms of tight end John Mackey, who sprinted 75 yards for a touchdown. The Cowboys subsequently blocked Jim O'Brien's extra point attempt to keep the score tied at 6–6, with O'Brien later saying that he was "awfully nervous" and hesitated a second too long before kicking it. 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. Third quarter The second half was a parade of turnovers, sloppy play, penalties, and missed opportunities. Colts returner Jim Duncan fumbled the opening kickoff of the second half and Dallas recovered. Then the Cowboys drove to the Colts' 1-yard line, but Mike Curtis punched the ball loose from Cowboys running back Duane Thomas before crossing the end zone, and the Colts took over at the 1 as Duncan was