Agassi polished off former world number one Yevgeny Kafelnikov 6-3, 7-6, 6-4 to reach the U.S. Open fourth round.
The Briton swept past Fernando Gonzalez of Chile 6-3, 6-4 to win the $600,000 Washington Classic.
Federer became the first man from Switzerland to reach a Grand Slam semi-final since Marc Rosset at the French Open in 1996.
Roddick withstood a fierce onslaught from 12th seed Paradorn Srichaphan while Federer beat Feliciano Lopez.
Roddick defeated Tommy Robredo while Srichapan ended the run of 17-year-old Rafael Nadal.
Andu Roddick beat Radek Stepanek 6-3, 2-6, 6-2 to enter the third successive final at Queen's.
Britain's Greg Rusedski turned the Wimbledon air blue with a furious outburst of foul language during his 7-6, 7-6, 7-5 loss to Andy Roddick.
American Andy Roddick and Briton Greg Rusedski will be going head-to-head on Centre Court in the race to hit the world's first 150 miles per hour (241.4 kph) serve.
Andy Roddick swept to his first grasscourt title on Sunday after thrashing Sebastien Grosjean 6-3, 6-3.
Spain's Fernando Verdasco came back from the brink of defeat to beat the top seed 6-7, 7-6, 6-4 in the last 16 of the Rome Masters.
The 32-year-old continued the form that has brought him 22 victories in 23 matches this year, to reach the final of the U.S. Clay Court Championships on Saturday.
The top seed will face Kenneth Carlsen in the semi-finals after the unseeded Dane beat American Jan-Michael Gambill at the Kroger St Jude ATP event.
It took the 20-year-old American a minute short of five hours to make his 11-year advantage count against the valiant Moroccan, Roddick sealing a five set victory to reach his first Grand Slam semis.
Moroccan Younes El Aynaoui will need to produce more of the same magic to prevent Roddick from reaching his first Grand Slam semi-final.
Spanish teenager Rafael Nadal upset Russian 15th seed Mikhail Youzhny in a dramatic second-round battle.
The US ace broke his record with a 155mph (249kph) serve as the U.S. took a 2-0 lead over Belarus in their Davis Cup semi-final.
Andy Roddick beat Nicolas Massu after Fernando Gonzalez stunned James Blake in the Davis Cup quarter-final.
The Australian Open runner-up let slip a two-set advantage on the Davis Cup tie against Belarus.\n\n
He is the sixth American and just the 13th player in the history of the ATP rankings to finish the year at the top.
Andre Agassi and Andy Roddick stayed on course for an all-American U.S. Open final.
Agassi was beaten by Chilean Fernando Gonzalez while Roddick lost to Tim Henman in the semis.
Since an abject first-round defeat by Sargis Sargsian at Roland Garros the American has won 10 consecutive matches, all on grass
Australian Bernard Tomic's appeal to overturn a fine for not playing to "required professional standards" at Wimbledon earlier this month has been denied in a stinging rebuke by the Grand Slam board.
The world No. 1 came from behind to beat Andy Roddick 3-6, 6-3, 6-4 in the U.S. Clay Court Championships final on Sunday.
