New Orleans Saints defensive coordinator Dennis Allen left London, England, with fonder memories than his last trip in 2014.

He was working as the head coach of the Oakland Raiders at that time. At least, he was before the Miami Dolphins spanked Raiders 38-14, which dropped them to 0-4 that season. The team fired Allen on the Monday after the game while during a bye week. He coached the Raiders to a pair of 4-12 seasons in 2012 and 2013 before the 0-4 start that doomed him.

The Atlanta native earned a measure of revenge in London this time with a 20-0 victory over Dolphins. His defense gave up just 186 total yards to Miami. The game began with the Dolphins' opening drive of 81 yards and ended that same drive when Saints cornerback Ken Crawley picked off Jay Cutler in the end zone.

His defense recorded four sacks, five tackles for a loss, four quarterback hits and three passes defended. The interception was the fourth pick and fourth turnover in the last two games.

The win gave the Saints their first shutout since beating the Tampa Bay Buccaneers in 2012 and their first road shutout since a Christmas Eve victory over the Jets in 1995. It was also the second regular-season shutout in the history of the NFL's International Series, with the first being the Buffalo Bills' 23-0 victory over the Washington Redskins in Toronto, Canada, in 2011.

Allen has seen a dramatic improvement in his defense over the last two games, which started with a 34-13 win over the Carolina Panthers. After giving up more than 1,025 total yards and 65 points in the first two games, the defense has since allowed just 474 total yards and 13 points.

After Oakland fired him, Allen joined the Saints in 2015 as senior defensive assistant to work side by side with then-defensive coordinator Rob Ryan. He replaced Ryan in November 2015 after the Saints lost 47-14 to Washington.

New Orleans won three of its final four games after Allen's promotion. His work earned him the defensive-coordinator job for the 2016 season, as the Saints continued to rebuild their defense.

This is not Allen's first tenure on the New Orleans Saints' coaching staff, though. He served as defensive line coach from 2006 to 2007 before moving to secondary coach from 2008 to 2010. He was a member of the staff that led the Saints to victory in Super Bowl XLIV.

Just like his father, Grady, a former linebacker for the Atlanta Falcons, Allen played college football at Texas A&M University before entering an NFL career. He played for the Aggies from 1992 to 1995 and went to training camp as an undrafted free agent for the Buffalo Bills in 1996.

Allen began coaching as a graduate assistant at his alma mater from 1996 to 1999 while he was earning his master's degree in kinesiology. He then accepted a position coaching the secondary at the University of Tulsa from 2000 to 2001.

The Atlanta Falcons were the first NFL team to hire Allen, and he spent four years from 2002 to 2005 with the club. In his first two years, he was the defensive quality control while working with the secondary, and in the last two years, he was a defensive assistant and quality control with the defensive line.

After his first term with the Saints, Allen went to work as the defensive coordinator for the Denver Broncos in 2011, though the left the team to become the head coach for the Raiders after only one season.