He debuted at his new position in the season opener against the Arizona Cardinals and helped Dallas gain 444 total yards (188 rushing); both totals were the team's highest since 1996. He helped lead way as two running backs topped the 100-yard mark for just the third time in franchise history at Washington on October 4, Smith finishing with 120 yards and one touchdown while Chris Warren recorded 104 yards and two touchdowns. In November, he faced four of the NFC's top defensive ends in Hugh Douglas, Chad Bratzke, Simeon Rice, and John Randle. Allen's streak started at Philadelphia on November 2, when he limited Douglas to one tackle and no sacks. The following week against the Giants and Bratzke, his blocking helped Emmitt Smith rush for 163 yards on 29 carries, a 5.6 average. The Dallas offensive line allowed no sacks to the Giants defense that led NFL in sacks in 1998. In Arizona, Allen limited Rice to one tackle and was part of an offensive line that allowed no sacks to the Cardinals defense as well. He led the way for Smith's 118 rushing yards and three touchdowns. The Seattle Seahawks had the AFC's top sacking defense of 1998 (11 sacks for 22 yards) and came away with just one sack (on an Aikman fumble), while the Cowboys ran for 173 yards. He also limited Randle to one tackle and no sacks in 81 offensive plays against the Minnesota Vikings on November 26. He also helped set a new franchise record for pass attempts in a game without a sack (57) and led the way as Smith rushed for three touchdowns to tie Marcus Allen's NFL record of 123 career rushing touchdowns. In the regular season finale against the Redskins on December 27, Allen was part of an offensive line that saw Smith run for two more touchdowns to break NFL's all-time rushing touchdown record.