The Rotterdam side came from a goal down to secure the victory, firing them into Europe's premier competition for the first time since 2002
Feyenoord recorded a crucial 3-2 victory over Heerenveen on Sunday, a win which sees them qualify for next season’s Champions League playoffs.
Bas Dost had put the hosts ahead shortly after the interval, but an 11-minute blitz saw the visitors snatch the full three points. Rajiv van la Parra netted a consolation strike late on.
Heerenveen found themselves in a curious situation heading into their last encounter of the season. The Friezen only needed to avoid a draw, with a loss guaranteeing them a Europa League spot. Only a victory would ensure Feyenoord entered the Champions League playoffs.
The hosts dominated possession in the opening exchanges, but it was the visitors that drew the first two saves. Ruben Schaken was twice denied by Kristoffer Nordfeldt, the Dutchman testing the Swedish stopper with two close range efforts.
Filip Djuricic then saw his attempt at the other end fly inches wide, before Viktor Elm was denied by the inside of the post. Djuricic then appeared to put his side ahead, only to see his close range header fly wide with Mulder beaten.
The Friezen continued to dominate possession, but lacked the incisiveness to feed dangerman Bas Dost. Feyenoord opted to test the hosts on the counter, but resilient defending snuffed out any danger posed by passes from the visitors’ midfield trio.
With news of PSV’s two goal advantage away to Excelsior having been passed on to Ronald Koeman’s men, the Rotterdam side were aware only a victory would suffice. Both teams came storming out of the interval, with end to end attacking play the tone in the second half.
The hosts were quick to apply pressure around the area, and it was the prolific Dost who opened the scoring. Sven Kums was sent into space on the right flank before sending in a low delivery towards the 6-yard box, and the Eredivisie top scorer was on hand to put Heerenveen ahead.
Feyenoord’s response was immediate, with Otman Bakkal drawing the visitors level. The midfielder picked up the ball just inside the box before sending a coolly taken shot past the leaping Nordfeldt.
Both side squandered clear cut opportunities to take the lead shortly after. Substitute Elvis Manu failed to convert from close range with only the keeper to beat, before Djuricic scuffed a tame effort which didn't test Mulder.
Sekou Cisse would not make the same mistake, netting his seventh of the season in the 68th minute. The forward sent a raking shot into the net, leaving Nordfeldt helpless. Manu then completed the comeback minutes later, flicking the ball up with his first touch and volleying past Nordfeldt with the second.
Van la Parra bagged a late consolation strike, slotting past Mulder after some delightful build-up play from the hosts.
The win sees Feyenoord secure second place, a position which grants them a ticket to the Champions League Playoffs. Heerenveen finish the campaign in fifth, which sees them enter the Europe League group stage.