Dallas improved a four-point halftime cushion to 10 by turning back-to-back third-quarter possessions into field goals by kicker Greg Zuerlein.
The first, 45 yards, increased the Cowboys lead to 16-9 with 10:17 left in the third.
The second, a 39-yard effort with 2:13 left in the third, gave Dallas a 19-9 advantage.
The Steelers turned their last two possessions of the first half into nine points and made their way to the locker room at halftime, 13-9.
Boswell’s franchise-record 59-yard basket ended the second quarter.
Boswell missed wide left on a 54-yard attempt with two seconds left in the quarter, but the Steelers were guilty of a false start. Boswell stepped back 5 meters and this time split the uprights.
The Steelers had regained possession at the Dallas 39-yard line 52 seconds before the half on a forced fumble by nickel cornerback Cam Sutton and a recovery by Fitzpatrick.
The Steelers began their way up the field with a 17-yard touchdown pass from
Roethlisberger to wide receiver James Washington 1:10 before intermission. Boswell missed the extra wide left run attempt and the Cowboys led 13-6.
Roethlisberger limped to the locker room after the touchdown pass favoring his left knee.
Substitute Mason Rudolph led the four-goal drive from the field and completed two of three passes for 3 yards.
The Cowboys took a 3-0 lead from a 38-yard field goal by Zuerlein that ended a 12-game, 65-yard practice in 6:47 on Dallas’ first possession.
The Cowboys increased their lead to 10-0 on a 20-yard touchdown pass from Gilbert to wide receiver CeeDee Lamb and an extra point from Zuerlein with 7:45 left in the second. The scoring strike ended an eight-game, 65-yard practice in 3:41.
Dallas flashed back on a punt return that lasted 73 yards after an illegal blocking penalty was enforced in a 44-yard field goal by Zuerlein and a 13-0 lead with 3:46 to do the second.