Leon Flach scored in the 59th minute as the Philadelphia Union defeated FC Cincinnati 1-0 in the Eastern Conference semifinals at Subaru Park.
Andre Blake showed why he won MLS Goalkeeper of the Year for a record third time, making a number of spectacular saves to preserve Philadelphia's slim advantage.
The Union advance to the Eastern Conference final for the second straight year where they will face either third seed NYCFC, who defeated them last year or second seed CF Montreal with their semifinal set for Sunday afternoon.
Story of the match
Julian Carranza had the first chance of the match after just six minutes, gathering in a long ball from Kai Wagner and forcing Roman Celentano into a save from his close-range effort.
Moments later, an unmarked Daniel Gazdag sent a header from six yard away wide.
Cincinnati had a half-chance after 20 minutes as Brandon Vazquez, hero of the win over the Red Bulls in the first round, shot from distance with Blake smothering.
On the half-hour mark, the visitors ended a good passage of play as Obinna Nwobodo fired just wide of the post while at the other end Jack McGlynn got his shot all wrong.
As the half progressed, there were no more scoring chances and the teams went into the locker room goalless.
Five minutes into the second half, the Orange and Blue looked to finish on the counterattack as Junior Moreno curled one on target, but Blake pawed the ball wide.
On 59 minutes, the Union got the goal they were looking for. After a well-worked combination by Gazdag, McGlynn and Carranza, Gazdag was dispossessed, but Mikael Uhre kept the play alive and he found the onrushing Flach, who made no mistake from 15 yards away.
Almost immediately after the goal, Uhre had a a two-on-two chance, but his shot from outside of the box was easily gathered in by Celentano.
The Dane was replaced by Cory Burke in the 68th minute following a yellow card issued to Olivier Mbaizo for kicking the ball into Alvaro Barreal.
Blake ensured Philadelphia would stay in the lead, getting low to parry away Luciano Acosta's shot.
With 15 minutes to go, Cincinnati manager Pat Noonan brought on Sergio Santos, who was acquired from Philadelphia in a midseason trade.
Vazquez took the ball away from Jack Elliott in the Union box, but once again Blake stretched out to deny the Orange and Blue.
Looking to strengthen the midfield, manager Jim Curtin elected to bring on Matt Real for McGlynn with five minutes to go.
Wagner nearly whipped a ball from the wing right under the crossbar, forcing another stop by Celentano, and from the resulting corner three players missed. Burke curled one just wide in stoppage time.
Man of the Match: Andre Blake
With the stars all over the field, Blake remains the most important player on the team and he showed why in this match, making save after save to preserve the shutout and help Philadelphia into the conference final.