(The Sports Xchange) - Miami Dolphins center Mike Pouncey says he cannot stop smiling when anyone mentions Jay Ajayi.

"For him to be demoted, to being a backup and now being one of the stars of our team," Pouncey said of the Dolphins second-year running back, "I'm so proud of him.

"Jay's able to write his own story."

Ajayi, 23, was born in London to Nigerian parents. He moved with his family to the United States in 2000, and soon began playing the American version of football, a decision that has led him right into the NFL record books.

He penned an incredible chapter Sunday, becoming just the fourth player in NFL history to rush for more than 200 yards in consecutive games, leading Miami to a 28-25 upset win over the Buffalo Bills at Hard Rock Stadium.

Miami (3-4) won its second straight game. Buffalo (4-3) had its four-game win streak snapped.

Ajayi, who was left off the active roster for the season opener after he pouted when Miami signed Arian Foster to be the starting running back, ran 29 times for 214 yards (7.4 average) and one touchdown.

The previous week, he ran for 204 yards and two touchdowns against the Pittsburgh Steelers. Before that game, Ajayi, a former fifth-round pick from Boise State, had never even rushed for 100 yards in an NFL game. His previous high was 48 yards as a rookie.

And yet Ajayi, despite that thin resume, joined O.J. Simpson (1973 and 1976), Earl Campbell (1980) and Ricky Williams (2002) as the only NFL players to have consecutive 200-yard games.

Williams also has the Dolphins' two best single-game rushing performances, going for the franchise record of 228 yards in 2002. Williams' 216-yard effort, also in 2002, ranks second in Dolphins history. Ajayi's total ranks third.

"I've always had confidence in my ability," Ajayi said. "But back-to-back 200-yard games in the NFL is an amazing and crazy thing to do."

(Editing by Andrew Both)