Ferrer, who's won the tournament the last three years and also in 2007, overcame a slow start for a 6-7 (5-7), 6-3, 6-1 decision over Young. Ferrer won barely half the points on serve in the first set, saving 10 break points and still losing his serve three times.
But he dropped just 13 points on serve the rest of the way and didn't allow Young another break opportunity while piling up four breaks himself.
Jack Sock ousted second-seeded Tommy Haas 6-4, 6-4 in a close second-round match. Sock won more than two-thirds of the points on serve and saw just two break points on the day.
Steve Johnson also came away an upset winner, taking out fourth-seeded Kevin Anderson 7-5, 6-4. Both players won 70 percent of the points when serving but Anderson managed just one break chance, which Johnson saved, while Johnson claimed breaks in each set in advancing.
Third-seeded John Isner defeated Lukas Lacko 7-6 (7-1), 3-6, 6-2 behind 21 aces and losing his serve just once in 14 games and No. 5-seeded Philipp Kohlschreiber topped Horacio Zeballos 6-4, 6-2. However, Roberto Bautista Agut took out sixth-seeded Benoit Paire 6-3, 6-4.
Swim Week Miami Beach 2014 [PHOTOS]