LOS ANGELES -- Late into the evening after his first playoff victory two weeks ago, Los Angeles Rams head coach Sean McVay finally exhaled. The whirlwind week leading to a 30-22 win over the Dallas Cowboys in the NFC divisional playoffs behind him, McVay reflected on achieving a career milestone. Not surprisingly, his thoughts quickly turned to the Washington Redskins.

For four seasons, beginning in 2010, he was part of a Redskins coaching staff that included three assistants who would go on to become head coaches: McVay, Kyle Shanahan of the San Francisco 49ers and Matt LaFleur -- the new Green Bay Packers coach. It was a group that pushed McVay to always be at his best.

"How about those guys that we had there in Washington!" said McVay, whose Rams will face the New England Patriots in Super Bowl LIII. "Just so many great memories about the process and working with that group each day to put the players in the best position we could.

"It was just a real special time. You knew you were not only working with really smart, hard-working coaches, but you knew we were all focused on the same goals and trying to do it the right way to get there. You look at the success so many guys we had there have gone on to have, the coaches that they've become, and it makes you feel good that you were part of it."

McVay was a key member of a strong offensive staff assembled by then-Redskins head coach Mike Shanahan.

In 2017, the 49ers and Rams hired Kyle Shanahan and McVay, respectively, as head coaches. Then the Packers in this hiring cycle tapped LaFleur -- who worked on staffs under both Kyle Shanahan and McVay after they all left Washington -- to replace Mike McCarthy. During an era in which owners prefer to fill head-coaching openings with coaches who have experience on the offensive side -- and an era in which the development of young quarterbacks is paramount -- the branches of Mike Shanahan's tree are growing wide.

The Bill Walsh and Bill Parcells/Bill Belichick coaching trees are the greatest in NFL history.

Currently, Kansas City Chiefs head coach Andy Reid, who's from a branch of the Walsh tree, has the league's most successful group of former assistants. Both John Harbaugh of the Baltimore Ravens and Doug Pederson of the Philadelphia Eagles have won Super Bowls. Carolina Panthers head coach Ron Rivera led his team to a Super Bowl.

Over the past few years, though, Mike Shanahan's onetime underlings have come to occupy a prominent place in the game. In fact, McVay is literally changing the game.

When the Rams hired McVay on Jan. 12, 2017, he became the youngest head coach in the league's modern era at 30 years, 11 months. Last week, McVay, at 32, became the youngest head coach in NFL history to win a playoff game, according to the Elias Sports Bureau. (McVay turned 33 on Thursday.)

In only two seasons with the Rams, McVay -- named the 2017 Coach of the Year by the Pro Football Writers of America -- has directed a stunning turnaround.

Last season, the Rams ended a playoff drought of 12 seasons. McVay has led the franchise to consecutive division titles for the first time since the Rams had a run of seven straight from 1973 to 1979. He has an impressive regular-season record of 24-8. And he has been the perfect guide for two-time Pro Bowl quarterback Jared Goff, the 2016 No. 1 overall draft pick whom some league observers had unfairly labeled a bust after his rookie season under former Rams coach Jeff Fisher.

Mike Shanahan, who led the Denver Broncos to consecutive Super Bowl titles in 1998 and 1999, always figured McVay would go on to do big things.

Back in 2010, Shanahan was looking for an offensive quality control coach. He was familiar with McVay, having worked for the 49ers when McVay's grandfather, John McVay, was a longtime and high-ranking player-personnel executive in the organization.

Sean McVay, left, and Kyle Shanahan, right, coached together as assistants for four seasons with Washington. John McDonnell/The Washington Post via Getty Images

"I was going to interview a number of guys for the position," Shanahan said. "But after my interview with Sean, I said, 'Hey, we don't have to go any further. This is the guy we want.' He was such a student of the game.

"He wanted to know what's being done in the running game, the passing game, offensive line ... he wanted to learn everything. And he's very smart with a great work ethic. You could see it wasn't going to take him very long."

The NFL is a copycat league. Right now, because of McVay's success, much of the league is copying the Rams.

In addition to the Packers hiring LaFleur, McVay's offensive coordinator in L.A. in 2017, the Cincinnati Bengals reportedly plan to offer their top job to Rams quarterbacks coach Zac Taylor once the Rams' season ends. Many owners seem downright obsessed with finding the next McVay.

Although McVay is flattered by other teams' recognition of the Rams' accomplishments, "It's really not about me," he said. "It's always about what all of the coaches and the players and everyone does coming together and working for a common goal."

"What I think about is about the opportunities that Mike Shanahan gave me as an inexperienced coach," McVay said. "I think about watching a Kyle Shanahan work. Just seeing the stuff he was running, his approach to different scenarios, and getting another understanding of what you can do as an offense ... all of that helped me grow."

During his time with the Houston Texans under Gary Kubiak, who was Mike Shanahan's offensive coordinator with the Broncos, Kyle Shanahan developed a reputation as an offensive whiz. He burnished it during the 2012 season.

To maximize what then-rookie quarterback Robert Griffin III did best, Kyle Shanahan -- Washington's offensive playcaller at the time -- installed an innovative zone-read scheme. It worked: With Griffin rushing for 815 yards (and a 6.8-yard average), accounting for 27 total touchdowns and finishing with a 69.4 Total QBR (No. 7 in the league), Washington won the NFC East division title, and Griffin was selected as the Associated Press Offensive Rookie of the Year.

"You look at the success so many guys we had [in Washington] have gone on to have, the coaches that they've become, and it makes you feel good that you were part of it." Sean McVay

"That coaching staff, looking at the offensive side, really did a great job in 2012 with putting in a new system," said Mike Shanahan, arguably one of the greatest offensive tacticians and playcallers in NFL history. "They really investigated what was going on at the college level and the pro level.

"Kyle, Sean and Matt ... I felt very strongly about the job they did to put together an offense that fit the skill level of a guy like RG3. Not everyone, looking at our personnel and making adjustments, could do that. Certainly not as well as those guys did it. That's for sure."

With Kyle Shanahan directing the Atlanta Falcons' offense in 2016, the team led the league in scoring and reached the Super Bowl. Falcons quarterback Matt Ryan was selected as the Associated Press NFL Most Valuable Player.

During Shanahan's two seasons with Atlanta, LaFleur was the Falcons' QB coach. In 2017, LaFleur joined McVay in Los Angeles. This season, LaFleur moved to the Tennessee Titans, partly to call plays. Now, the Packers are counting on LaFleur to help Aaron Rodgers return to second-to-none status next season. The Packers chose wisely, Shanahan said.

"Matt's a really good coach," Shanahan said on the phone. "He was a big part of that staff we had in Washington, and he was also with me in Houston, so it was eight years total. But the funny thing is that it didn't even hit me that there were [three future head coaches on Washington's staff] until I saw your text.

"It's cool for my dad, because he was the one who gave us all those opportunities. He had us all in that building. He gave me the room to continue to grow and work and really try to do some things that weren't being done. Maybe I'll really appreciate it more later. Right now, I'm just thinking about how much it means for him."

Strong ties bind Shanahan, McVay and LaFleur -- but business is still business for the three young head coaches.

The 49ers reportedly denied the Packers' request to interview three well-regarded San Francisco assistants -- including LaFleur's younger brother, Mike. Over the past two seasons, the Rams have finished atop the NFC West and the 49ers have finished last. Obviously, that's a fact that won't put a smile on Shanahan's face. Although McVay has immense respect for Shanahan, McVay hopes to crush his colleague's team whenever they meet. Now, LaFleur will be among their sideline counterparts.

"The friendship will still be there," Shanahan said. "But we all have a job to do."

Based on how Mike Shanahan's tree is growing, it appears that those former Redskins assistants are doing their jobs quite well.