Leave it to Roger Federer to do something on a tennis court no one has seen before.

At 34, with two sets of twins at home and a gaggle of entitled teenagers making noise at his workplace, Federer is suddenly looking as youthful and spry as he has in many a year. And the man with the most complete arsenal of weapons in the history of the game is still adding to his quiver.

Two weeks ago at the Emirates Airline US Open Series event in Cincinnati, Federer unveiled a sneaky, audacious new tactic that left opponents baffled and immediately went viral among tennis fans.

Against 6-foot-8, big-serving Kevin Anderson, Federer suddenly sprinted forward as Anderson tossed the ball to serve. Federer was instantly within inches of the service line, where he half-volleyed the return. In a flash, Federer was all over the net, before Anderson could react.

It was like a concert kid bum-rushing the stage. Take that, young punks!

Rushing toward, rather than backpedaling away from, 110-mph serves might be someone else’s idea of a kamikaze play. But for Federer, it’s not a trick shot. It’s an actual tactic. And it’s shockingly effective.

Employed selectively, it adds an element of surprise, robbing opponents of crucial time and heaping pressure on that first shot after the serve – already one of the most difficult shots to set up for. The ball is on the server nearly as soon as he has completed his service motion.

If it looks like something you might try goofing around on the practice court, well, that was in fact its genesis. “I did it in practice more as a joke, and I tried it again and again and again, and it just seems like it's not that hard for me to do,” said Federer. His coach Stefan Edberg, no slouch himself around the net, encouraged him to give it a whirl in a real match.

So against Anderson, as well as Andy Murray and Novak Djokovic – hardly the kind of chumps you toy around with – Federer stormed the net while receiving serve. Against Djokovic in the final, Federer employed the ambush return 11 times, winning seven of them (including in the first-set tiebreak). Only once was Federer forced to hit a volley. Four of the world No. 1’s attempted passing shots were dumped into the net; on another point, Djokovic, possibly distracted, double faulted.

Both Murray and Djokovic tried hitting passing shots as well as lobs. John McEnroe suggested the next guy Federer does it against go old school and blast the ball straight at Federer’s chest, a la Ivan Lendl.

What to call this, the receiving equivalent of serve and volley? Chip-and-charge has been around since tennis balls were white, but this is a decidedly new twist. Federer’s own team gave it the unwieldy moniker SABR (Sneaky Attack by Roger).

“It can break somebody's rhythm, maybe can play with the mind a little bit,” admitted Federer. 

It’s hard to imagine anyone other than Federer attempting such a damn-the-torpedoes tactic. “He’s got mad skills for 34,” said Brad Gilbert. That Federer still has such incredible movement and reflexes, and hand-eye coordination at 34 is remarkable, a confirmation of his unequalled racquet skills. As is the fact that the Swiss maestro, now back up to No. 2 in the world, is still adding new wrinkles to his game.

So far, no one has questioned the tactic’s sportsmanship, although it is technically moving during one’s opponent’s serve – and intentionally distracting. Maybe that’s because the innovator is Roger Federer, perhaps the most respected and gentlemanly player in the game.

Federer was once a staunch traditionalist, who refused to make the change to a more forgiving, larger-head racquet and whose disdain for the drop shot and instant replay was well known. Yet in his 30s, a forward-looking Federer has embraced all of these. He went with a lighter, larger stick; he delights in hitting wicked sidespin droppers; questions line calls like everyone else; and has even been spotted wearing fuchsia-colored kits.

Once content to sit back and rally endlessly with the likes of Nadal and Djokovic, despite the strengths of his all-court game, Federer has recognized that with his superb hands and movement, as well as obvious interest in shortening points, he needed to move forward more. So he is again serving and volleying and looking to crash the net whenever possible.

He’s just taking that to an extreme now. Opponents are probably lucky that he can’t actually volley back a serve. Even Roger would lose that point.