The magic of the FA Cup was on full display at Vale Park on Sunday as League One strugglers Port Vale pulled off a monumental giant-killing. Despite sitting at the very bottom of the third tier, the Valiants defied a gap of 57 places in the football pyramid to eliminate Premier League side Sunderland with a gritty 1-0 victory.The Black Cats failed to exert their top-flight authority against an opponent many expected to be swept aside. The atmosphere in Burslem was electric from the first whistle, as the home crowd of 10,685 sensed the potential for a historic afternoon against their illustrious visitors.The decisive moment arrived in the 28th minute through Ben Waine. After a corner was kept alive by the determined Vale attack, the forward - who coincidentally identifies as a fan of Sunderland's fiercest rivals Newcastle - leaped highest to send a looping header into the back of the net. The goal sent the home supporters into a state of pure delirium as they took an unlikely lead. Sunderland, led by their top-flight stars, struggled to find any rhythm in response to the setback. While the Premier League side dominated possession, they lacked the clinical edge required to break down a Port Vale side playing with the defensive doggedness of a team much higher up the league standings.According to Opta, this victory marks a monumental milestone for Port Vale, as they have now reached the FA Cup quarter-final for only the second time in their history (the first being in 1953-54). Furthermore, by toppling the Black Cats, the Valiants have ousted a Premier League opponent from the competition for the first time since their famous triumph against Everton in the 1995-96 fourth round.The second half was largely a story of backs-to-the-wall defending for the League One basement boys. As the clock ticked down, Sunderland threw numbers forward in a desperate attempt to force extra time, but they were met with a wall of white shirts at every turn. Vale’s organization and spirit remained unbroken throughout the final stages.Despite the gulf in quality and resources, the Black Cats simply did not do enough to warrant a comeback. Their star-studded lineup was stifled by the tactical discipline of the home side, who reminded the footballing world why this competition remains the greatest stage for the improbable. The final whistle prompted scenes of wild celebration as the underdog story was completed.Add GOAL.com as a preferred source on Google to see more of our reportingPort Vale now turn their attention to the quarter-final draw, which is scheduled to take place on Monday. The victory marks a significant high point in an otherwise difficult season for the club, providing a much-needed boost to their supporters. For the Valiants, the prospect of another massive tie in the last eight is now a reality.Sunderland, meanwhile, will be left to reflect on a missed opportunity and a humiliating exit at the hands of the lowest-ranked team left in the competition. The focus for the Black Cats must now shift back to the Premier League and their push for a top ten finish, as the weight of this sensational upset is likely to linger long in the memory of their traveling fans.