Mardy Fish led the top four men's seeds into the second round of the ATP/WTA Washington Open after a thunderstorm which delayed the start of play by an hour.
The American who is missing the London Olympics to play on his home hardcourts this summer, rallied after a slow start to defeat Germany's Bjorn Phau 4-6, 6-1, 6-2.
Fish was playing his first full hardcourt match since last March after quitting a fortnight ago in Atlanta due to an ankle injury.
Fish, ranked 13th and now over a recent health scare from an accelerated heartbeat, was joined as a winner by tournament debutant and second seed Alexandr Dolgopolov. The Ukrainian beat Flavio Cipolla 6-1, 6-3.
Number three Kevin Anderson of South Africa followed the winning trend as he beat Estonian Jurgen Zopp 6-3, 6-2.
Veteran Tommy Haas, a former number two who has lifted his ranking back to 36th after recovery from hip surgery, made his return to the hardcourts for the first time since last March and came up a 6-4, 6-2 winner over fellow 34-year-old Michael Russell.
The German who reached a clay final this month in Hamburg is playing this week instead of London after not being given a nomination as a wild card by German tennis bosses.
Haas has played at least semi-finals in three of his last six ATP events, including his first title in three years at Halle, Germany, on grass in June.
"I'm happy with how I played today," said the winner. "This was my first hardcourt event since Miami (March). I respect Michael a lot. He's my age and has been playing well.
"It took me some time to regain confidence after surgery, but now I know that I can compete with the guys again. I'm really starting to believe in my chances again."
The winner of 19 career titles improved to 20-9 on the season and next plays Argentine Leonard Mayer.
Elsewhere, last week's Los Angeles semi-finalist Xavier Malisse rallied past Frenchman Paul-Henri Mathieu 4-6, 6-2, 6-1, while Spain's Ruben Ramirez Hidalgo put out Australian Matthew Ebden 6-3, 6-2.
Swiss qualifier Marco Chiudinelli, a childhood friend of Roger Federer, battled to beat Horacio Zeballos of Argentina 7-5, 7-5 to reach a second round for the first time since February.
In women's play at the new combined event, top seed Anastasia Pavlyuchenkova of Russia won her opener against Serb Bojana Jovanovski 6-4, 6-3. Fourth seed Vania King beat fellow American Jennifer Elie 6-3, 6-4.