It's been a thoroughly unpredictable season of football in the English Premier League, so it stands to reason that the 2015/16 FA Cup would take an unpredictable turn as well. Following a winding and at times bizarre season, the FA Cup exploded in a series of upsets and close calls in the quarterfinals. Now, with most of the tournament's supposed frontrunners eliminated and one replay match left to decide the full semi-final draw, we are going to take a look at what happened and what could happen going forward.

The Tournament So Far

At the outset of the 2015/16 FA Cup, most of the teams earned assumed frontrunner notices were the teams that always get those notices: Premier League giants like Chelsea, Arsenal, Manchester City, and Manchester United. After the third round-the first to feature most of the supposed top contenders-there was little reason to think that one of those "Big Four" clubs wouldn't win the title. All four teams won their third round games, with Manchester City notching the biggest victory of the round in a 3-0 win over Norwich City. Other Premier League favorites like Liverpool and Tottenham Hotspur also pushed through to the fourth round.

But then things started to go south for the Premier League's top soccer clubs. Liverpool lost to West Ham in a fourth round replay match. Crystal Palace eliminated Tottenham in the sixth round. That round also saw Chelsea and Manchester City drawn against one another, with the reigning Premier League champions crushing Man City 5-1.

The Quarterfinals

Still, coming into the quarters, three of the Premier League's heavyweight clubs-Chelsea, Manchester United, and reigning FA Cup champions Arsenal-were still alive. Furthermore, none were drawn against each other in the match-ups. Most pundits predicted that, even with all three teams weathering up and down campaigns in the domestic league, they would still all push through to the semis.

Instead, at very most, only one of them will be reaching the semis-and even that isn't a sure thing at this point. The question is this: what happened to the Premier League's supposed heavyweights, and why have they consistently failed to score wins at key moments throughout the 2015/16 season?

Arsenal vs. Watford

The most surprising loss on the table for the quarters was Arsenal. The Gunners are the most successful football team in FA Cup history, having notched their 12th last year. (Manchester United, if they manage to win the title this season, will tie that record.) Furthermore, Arsenal were enjoying something of a winning streak in this tournament, having beaten Aston Villa and Hull City (respectively) to clinch the trophy in 2015 and 2014.

Now, though, after a Sunday, March 13th match against Watford, the Gunners won't have a chance to defend their title, or to become just the third club ever to win the FA Cup three years in a row.

By all accounts, Arsenal were the favored team to win. Not only were the Gunners the reigning FA Cup champions, but they also had the home field advantage for the quarterfinals match and hadn't lost a game to Watford since 1988. Watford weren't even a top-flight soccer squad a year ago. Following a promotion from the Championship at the end of last season, the Hornets are competing in their first Premier League season in eight years. Arsenal beat them 3-0 in October.

Even with so many factors on their side, though, the Gunners couldn't grab a win on March 13th. They won the possession game 66% to 34% and had way more shots on goal than the Hornets did. But Arsenal's shots went wide while Watford made theirs count. Indeed, after two early first half goals, the visitors were leading 2-0. A late goal from Danny Welbeck-recently recovered from a long injury-saved Arsenal from a shutout, but couldn't save the football club from an FA Cup elimination.

The Other Matches

Most of the other quarterfinal matches were only slightly less shocking than Arsenal's against-all-odds defeat. As expected, Crystal Palace beat second-tier Reading (with a score of 2-0) to reach the semis. But events went against expectations in the other two matches, where Chelsea's season continued to hit bum notes and Manchester United continued to underperform.

Chelsea have, for the most part, had a dreadful season. They lost so many of their Premier League games so early in the season that they quickly fell out of contention to defend their title, they sacked Jose Mourinho, and they crashed out of the Champions League in the round of 16.

Despite these woes, though, it seemed that, if the Blues did have a chance at some silverware in 2016, the FA Cup was the competition where it was most likely to happen. Indeed, Chelsea had been nearly perfect up to the quarterfinals, easily winning their third round game against third-tier Scunthorpe United and then crushing the fourth and fifth round opponents (Milton Keynes Dons and Manchester City) in a pair of triumphant 5-1 victories.

Chelsea's string of good FA Cup fortunes came to an end on Saturday, March 12th in an away match against Everton. The Blues have struggled against Everton this season, losing 1-3 to the team in the fall and then only barely salvaging a 3-3 draw in January. Chelsea held their own for most of the FA Cup battle, but a pair of late goals for Belgian great Romelu Lukaku-one of the Premier League's breakout stars this season-put the Blues behind 0-2 with less than 10 minutes to go. In the end, Chelsea couldn't rally, and Everton won the game and the semi-final spot.

Manchester United also fell behind late in their quarterfinal match, taking on a 0-1 deficit at the 68th minute, following a goal from West Ham United's Dimitri Payet. The Red Devils have struggled lately, with captain and offensive leader Wayne Rooney currently out with a knee injury. Marcus Rashford, Rooney's inexperienced 18-year-old stand-in, has had moments of glory but hasn't been able to mimic his elder's talent for leadership.

Indeed, it wasn't Rashford who saved the day for United against West Ham, but Anthony Martial. Another largely green youngster, Martial has had his own consistency issues this season and clearly still has plenty to learn. However, his 83-minute goal-scored on an assist from Ander Herrara-did net the Red Devils a 1-1 draw and kept the team alive for a replay match against West Ham on Tuesday, March 22nd.

The Semi-Final Draw

With the Manchester United/West Ham United match-up not completely decided, the draw for the FA Cup semi-finals is only three-fourths completed. Crystal Palace (H) will play Watford (A) on April 23rd or 24th. The other drawing will pit Everton against either Manchester United or West Ham, depending on which team wins the replay. Everton will have the home field advantage.

None of the remaining five teams have won an FA Cup title since 2004 when Manchester United won their 11th trophy in the tournament. Everton last won in 1995 (their fifth title) while West Ham United have won the FA Cup three times, most recently in 1980. Neither Crystal Palace nor Watford has ever won this particular competition.

Those statistics show just how wide open this year's FA Cup tournament is. Of the last 10 FA Cup finals, Chelsea won four, Arsenal won two, and Manchester City won one. Not since 2008 (when Portsmouth beat Cardiff City to win the title) has this contest been so devoid of an obvious frontrunner. Needless to say, things could get interesting next month when semi-final play begins.

Place Your Bets!

What are your predictions for the final stages of the 2015/16 FA Cup? Will Manchester United rally from an uneven season to win their first FA Cup in a decade (and tie Arsenal for the all-time record)? Will Everton or West Ham United end their long droughts without a trophy in this tournament? Or will Crystal Palace or Watford become a first-time FA Cup champion?

All of these outcomes seem entirely feasible-a fact that should make the remainder of this year's FA Cup nearly as interesting to watch as the Premier League! But at Soccer Box, we want to hear your predictions for what might happen. Find us on social media to share your thoughts! We have an active daily presence on multiple platforms including Facebook, Twitter, and Pinterest.