Europe's top performers for May were whittled down to a three-man shortlist in consultation with WhoScored.com and ESPN FC's writers.
Lionel Messi, Cristiano Ronaldo and Filip Kostic were those in contention, and we have an upset. Despite Lionel Messi being in absolutely scintillating form, it's Stuttgart's 22-year-old Kostic who takes home the Player of the Month award for May in a landslide.
News of the vote was picked up by Stuttgart daily newspaper Stuttgarter-Zeitung, and subsequently passed around in Germany and Kostic's home country of Serbia, and his fans voted in force. Kostic secured nearly 62 percent of the vote, nearly doubling the ballots received by incumbent Messi's 31.5 percent.
Ronaldo finished a distant third. Even though Ronaldo enjoyed the strongest May of any of the finalists, statistically speaking, the Portuguese won less than 7 percent of the vote.
Whether you agree with Kostic's upset or think someone else should have gotten the nod, let us know on Facebook and Twitter -- using the hashtag #espnfcplayer -- as well as in the comments section below.
NOTE: Only players with three or more appearances were considered.
FILIP KOSTIC (Stuttgart)
Filip Kostic's time at Stuttgart had not gone according to plan. After arriving at Stuttgart from Dutch side FC Groningen for €6 million in the summer, the Serbian made only three starts through the end of October. He would make just eight more as the calendar turned to April. Then he began to turn it on.
Kostic started and played 90 minutes in each of Stuttgart's final eight matches as the club fought to remain in the Bundesliga for 2015-16. In four matches in May, Kostic notched two goals -- doubling his season tally to that point -- and added significant width to Stuttgart's attack. The man who earned the nickname "Arjen" during his time in the Eredivisie averaged nearly five dribbles per game throughout the season, but that number increased to nearly seven per game in May.