The 1972 Miami Dolphins remain alone in Perfectionville.

Pittsburgh let a two-touchdown lead get away, and Washington’s Dustin Hopkins hit two 45-yard field goals late in the fourth quarter Monday night to hand the host Steelers their first loss of the season, 23-17.

Hopkins gave Washington a 20-17 lead with 2:07 left, and on the Steelers’ first play from scrimmage after the kickoff, Montez Sweat tipped a Ben Roethlisberger pass and Jon Bostic picked it off at the Pittsburgh 25.

Four plays later, Hopkins was called upon again, and he drilled another 45-yarder, securing the surprising victory and lifting Washington into a first-place tie with the New York Giants in the NFC East. It was the third consecutive victory for Washington (5-7).

Pittsburgh (11-1) had led 14-0 in the first half and 14-10 entering the fourth quarter but missed a chance to clinch a playoff spot.

The result leaves the legendary ’72 Dolphins, who went 14-0 in the regular season and 3-0 in the playoffs, as the only team to win every game from beginning to end in the league’s 101-year history.

Washington forged a 17-17 tie on Alex Smith’s 15-yard touchdown pass to a wide-open Logan Thomas with 9:09 remaining. Smith was 31 of 46 for 296 yards and one TD, and teammate Peyton Barber rushed for a score.

Roethlisberger, who on Saturday was listed as questionable because of a knee injury, was 33 of 53 for 305 yards and touchdown passes to Diontae Johnson and James Washington. His only interception was the one in the final seconds.

Washington rookie Antonio Gibson, his team’s leading rusher, left in the first quarter because of a toe injury on his left foot.

Pittsburgh opened the second quarter with the game’s first sustained drive, 72 yards in 14 plays, with Roethlisberger throwing 3 yards to Johnson at the left edge of the end zone for a 7-0 Steelers lead.

Shortly thereafter, the Steelers got the ball on downs at the Washington 31 and moved to the 1 but got stuffed by Washington on four downs, yielding back possession.

Washington couldn’t gain a first down, and after a punt, the Steelers got the ball at midfield. On first down, Roethlisberger threw to James Washington, who sidestepped Deshazor Everett’s tackle attempt just outside the 40-yard line and went down the left sideline for a 50-yard touchdown to make it 14-0.

Hopkins’ 49-yard field goal with one second left in the first half pulled Washington to within 14-3.

In the third quarter, it was Pittsburgh’s turn to try for a goal-line stand, but Barber plowed in from 1 yard out to close the score to 14-10.

A Steelers drive that bled into the fourth quarter ended when Matthew Wright, making his NFL debut with Chris Boswell hurt, kicked a 37-yard field goal for a 17-10 lead.