Ernst, the fourth alternate entered into the PGA's Wells Fargo Championship in North Carolina, defeated David Lynn on the first playoff hole in rainy and cold conditions Sunday for his first professional championship.
He turned professional last year and was 1,207th in the rankings going into the Wells Fargo. The win lifts him to 123rd.
Rumford, a 14-year professional, ended a 5 1/2-year winless span April 28 with a European Tour win in South Korea and backed that up with a title Sunday at the Volvo China Open. He's gone from 253rd to 122nd to 76th in the rankings the last three weeks.
Tiger Woods has a ranking average of 11.79 for the No. 1 spot, with Rory McIlroy second at 10.40. Adam Scott (7.81) is third with Justin Rose fourth at 6.67 and Luke Donald's average of 6.46 fifth-highest.
Mickelson average is 5.32 while Kuchar's is 5.28.