Sam Querrey reached his third consecutive ATP final by upsetting top-seeded German Tommy Haas 6-3 7-5 at the LA Open on Saturday.
Tommy Haas went out of the Munich Open in the first round, losing 6-4, 6-4 to Sebastien Grosjean.
World number one Aryna Sabalenka reached the last 16 at the Miami Open when Elena-Gabriela Ruse retired injured on Saturday, while men's top seed Alexander Zverev beat Jacob Fearnley 6-2, 6-4 to reach the third round.
The German produced a stunning performance to win the Memphis International for the third time.
Big-serving American Sam Querrey shrugged off a nervous second set to clinch his second ATP title with a 6-4, 3-6, 6-1 victory over Australian qualifier Carsten Ball at the LA Open on Sunday.
Roger Federer beat Tommy Haas 6-1, 6-3 in the fourth round in Miami.
Top seed Rainer Schuettler beat Swede Robin Soderling 6-4, 7-6 in the first round of the Munich Open.
Defending champion Novak Djokovic, playing his second match in four hours, stormed into the semis of the Toronto Masters on Friday while Canadian Milos Raonic failed to deliver a similar outcome for the home crowd.
Both scored straight-set victories in Friday's semi-finals.
In the Dubai Open semis, Federer plays Tommy Haas, while Youzhny takes on Robin Soderling.
World number one Roger Federer breezed through to the Halle Open semi-finals with a 6-3, 6-4 win over Germany's Philipp Kohlschreiber.
In the semi-finals, Agassi beat German fourth seed Tommy Haas, while Johansson beat fellow-Swede Michael Ryderstedt.
Andy Roddick and Andy Murray eased into the quarterfinal of the Memphis International.
The world number one was pushed by the Russian but survived to book his place in the last four of the Australian Open against German Nicolas Kiefer.
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.
The 35-year-old's first match back in action last week at the Stuttgart Open was a flop when he suffered a shock loss to German veteran Tommy Haas, ranked 302 at the time, despite leading for a set and a half.
Fifth seed Roger Federer was dumped out of the Shanghai Open, losing to Frenchman Gael Monfils 6-4, 6-7(5), 6-3 in the third round on Thursday.
World number three and defending champion Roger Federer suffered a surprise defeat in the second round of the Shangahi Masters on Tuesday, losing 7-6(4), 2-6, 6-3 to Spain's Albert Ramos-Vinolas.
Roger Federer booked his place in the ATP World Tour Finals for a record-tying 12th consecutive year when he dismissed South African Kevin Anderson 6-4, 6-4 to reach the third round of the Paris Masters on Wednesday.
It was a routine win for top seed Novak Djokovic, but his satisfaction at reaching the Wimbledon quarter-finals without dropping a set was mixed with relief after some tricky moments against German veteran Tommy Haas on Monday.
The Frenchman, seeded five, had no answer to left-hander Muller's swinging serve as he bowed out 6-4, 6-4.
Novak Djokovic outclassed Finland's Jarkko Nieminen 6-4, 6-2, 6-3 to move safely into the Wimbledon third round on Wednesday.
The lanky wild card kissed the Montreal court after completing a rousing 3-6, 6-4, 7-6(4) triumph as the 18-year-old became the youngest player to ever reach the quarter-finals of an ATP Masters 1000 event.