Marginal gains: How set piece specialists are thriving in the Premier League

Aston Villa's set piece coach Austin MacPhee is one of several designated set piece coaches who are quietly having a profound impact on the Premier League .

At Aston Villa, Villa scored more goals from set pieces last season than any other team in Europe 's biggest leagues.

At Brentford , Keith Andrews has made a specialty of the opening kickoff as a scripted play.

Brentford scored off their first corner in their Premier League opener this year , and scored again in the first corner of their first Champions League game.

Free kicks and corners have long been perceived as almost random exercises.

With the ready availability of data, it has become clear that optimizing set pieces can yield a dozen or more goals annually .

Brentford owner Matthew Frank insists he will never again work without a set piece coach.

Arsenal has scored a league-leading eight goals off set pieces in the Premier League this season .

Brentford practice set pieces at the end of every training session to maximize opportunities.

"We, of all clubs, know how much a set piece is worth," Brentford's Frank Frank says.