Beating his younger compatriots is getting tougher for Lleyton Hewitt, but that’s exactly what the Australian veteran did in Washington.

The former world No.1 won the battle of the nation’s top-ranked men at the ATP event on Tuesday, toppling Marinko Matosevic 6-4 6-3 to advance to the third round.

Hewitt, winner of the tournament in 2004, next faces either No.2 seed Milos Roanic or American Jack Sock.

“It’s a lot harder playing fellow Australians now because I’ve tried to help a lot of the other guys,” he said.

“Obviously as the elder statesman, especially in terms of Davis Cup, (I’ve been) trying to get these guys up there and get them a lot better.

“You work on some of their weaknesses and then it can cost you when you’re playing against them.

“I’ve tried to help Marinko – especially probably the last four of five years – in taking the next step, and it’s not easy playing against him.

“In the end, I was just happy to get the win.”

The 33-year-old, who enjoyed a first-round bye, said he also found it difficult to adjust to playing on hard courts three weeks after his title win on grass in Newport.

“So that was important to get it under my belt (before next month’s US Open),” he said.

Hewitt was the only Australian left in the main draw after what was an otherwise disappointing day for the men from Down Under.

Bernard Tomic had his six-match winning streak snapped with a second-round defeat to Denis Istomin of Uzbekistan.

The 6-4 7-6 loss came less than a fortnight after the 21-year-old won his second ATP career title in Bogota, Colombia.

Countrymen Sam Groth and James Duckworth also crashed out of the Washington event on the back of first-round defeats.

Groth battled Dudi Sela for two hours and fired 16 aces, only to lose 7-6 3-6 6-4 to the Israeli – who was beaten by John Isner in Sunday’s Atlanta Open final.

Wildcard Duckworth went down 6-3 7-6 to American Steve Johnson, whose victory earned him a second-round clash with compatriot and No.5 seed Isner.