Eighth-seeded Donald Young knew what to expect from a player he's often practiced against.
That made it easier pulling off the upset over top-seeded Steve Johnson.
Young beat fellow American Johnson in the quarter-finals of the Hall of Fame Tennis Championships on Friday, 6-2 6-3.
"I played well. Stevie, we know each other well and we train a lot in the off-season and practice throughout the year, so there's no mysteries there," the 26-year-old Young said.
"I know how to beat him. You're going to have to play well, so I knew exactly what I had to do, and fortunately I was able to do it."
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Young saved all five break points in the match.
The 26-year-old Johnson connected on just 46 percent of his first serves. Johnson is ranked a career-best 25th this week.
Johnson, who will be representing the United States at the Rio Olympics next month, is glad to see a friend doing well.
"It's great. I'm happy for him. DY is a great friend of mine, so hopefully he can continue on," he said. "Of course there's pressure, but you guys put it on us more than we do, so I've got no issue with it."
Young entered the week ranked 61st.
In other quarter-final play, second-seeded Ivo Karlovic of Croatia reached his third consecutive semi-finals on Newport's grass courts, beating Switzerland's Marco Chiudinelli 6-3 6-4.
Karlovic lost in the final the last two years.
In another quarter-final match, third-seeded Gilles Muller of Luxembourg rallied past France's Adrian Mannarino, the No. 6 seed, 2-6 6-1 6-2.
Marcos Baghdatis of Cyprus advanced to the semi-finals on Thursday.
The semis will be played on centre court after enshrinement ceremonies for the 2016 class into the International Tennis Hall of Fame.
Marat Safin and Justine Henin head this year's class.
