NEW YORK—Roger Federer has drawn energy from the electricity of New York night crowds in posting a near spotless record beneath the bright lights of the U.S. Open. Tonight, the Swiss faced a power surge from Sam Groth, but responded with timely breaks to pull the plug on the explosive Australian.

Federer broke five times and reeled off the final four games to defuse Groth, 6-4, 6-4, 6-4, in an entertaining second-round victory. It wasn't an immaculate performance—Federer squandered an early break in the second set and fell behind a break in the third—but the Swiss answered with some shrewd passes and snappy returns. Federer hit a clean return winner off a 142 M.P.H. serve and blocked back a 147 M.P.H. rocket—the fastest serve of the tournament — and barely looked rushed on either strike.

Watching massive servers trying to beat Federer with pure pace is like watching a heavyweight fighter trying to knock out a shadow—they swing with menacing intentions but often punch themselves out. The five-time U.S. Open champion's ability to shorten his backswing and redirect pace has helped him short-circuit crackling servers ranging from Andy Roddick (21-3 career record) to Ivo Karlovic (11-1) to Milos Raonic (6-0).

The 26-year-old, whose habit of uttering "sorry mate" when catching his toss is reminiscent of compatriot Patrick Rafter, saved a second break point with a body serve in the third game. Mixing the pace and height his shots shrewdly, Federer hit some dipping passes, forcing the muscular, 6'4" Groth to scrape some low volleys off his shoelaces. The serve-and-volleyer won just 26 of 59 trips to net as his biggest blasts sometimes came back before he reached the service line. When Groth bungled a high backhand volley, Federer was handed a break and a 4-3 advantage, and the second seed served out the 29-minute opener at love.

The pair exchanged donations of sloppy service breaks to start the second set. A former Aussie Rules football player, the hard-charging Groth is a rugged physical presence and spirited competitor, but subtlety is not his strong suit. He unleashed some blistering serves, but they did not faze Federer, who finished with one more ace (nine to eight) than his opponent.

Rushing the net, Federer drew an errant backhand pass to earn break point and broke for 5-4 when a stretched-out Groth poked a forehand deep. Serving for the set, Federer capped a 17-shot rally sliding into a beautifully-controlled backhand lob that elicited an appreciative roar from the crowd. He closed at love again for a two-set lead after just 64 minutes.

Credit Groth for his unrelenting aggression in his first match against a Top 10 opponent and second career U.S. Open main draw match. The feisty Aussie hit a fine forehand stretch volley and broke with a clenched fist for 4-2 when Federer buried a forehand into the bottom of the net. But his lead was short-lived as Groth netted a backhand volley, then tapped another volley into the tape to give back the break. A leg-weary Groth then double-faulted to donate a second straight break.

The 17-time Grand Slam champion closed it out by sliding an ace out wide to raise his record to 26-1 in U.S. Open night matches before a buzzing crowd, while the ringing—in his ears and arm—reverberated.

"It's always an unbelievable challenge playing [big servers]," Federer told ESPN's Brad Gilbert afterward. "He's got unbelievable power so my arm's still vibrating a bit."

A decade removed from his first U.S. Open title, Federer will next face Marcel Granollers, who withstood 31 aces from Karlovic in a five-set victory. Federer has won all four sets he's played against the 42nd-ranked Spaniard.