Baseball took over London's Trafalgar Square on Friday afternoon. The iconic setting, which is playing host to the London Series fan festival this weekend, wasn't just dishing up hot dogs and cold glasses of beer, though: There were home runs to be smashed right past Nelson's Column -- at least, in a virtual world. 

That's right, Friday saw players representing the Cubs, Cardinals, Red Sox and Yankees face off for Home Run Derby X: The Cage. Taking a page out of esports, each batter took real hacks against real baseballs before their fly balls were charted in an augmented reality version of the square.

• London Series

Now, here were the rules:

Every batter got 20 swings with a 10-second timeout in the middle of their cuts. There were bonus points available on home run hat tricks (three consecutive swings resulting in home runs), if the ball flew through a 2x or 3x multiplier, and the final five swings were all worth double points.

Be careful, though: Fail to hit a homer and the ball might land in the catch zone, subtracting points from the batter's total.

With London's baseball-hungry crowd in attendance, here's how the whole thing went down:

Semi-final 1: Cubs 61,750 - Cardinals 45,050

In a fitting first HRDX game for the London Series, the contest came down to two Great Britain national team stars.

But first, Dexter Fowler, who helped the Cubs break their 108-year-old curse in 2016, faced off against David Eckstein of the Cardinals. Though Eckstein hit just 35 home runs in his big league career, it didn't matter in the Cage: The former shortstop smashed seven homers and topped Fowler with 19,350 points -- even as the Cubs outfielder appeared to be messing with Eckstein on his final swing.

After USWNT teammates Alex Hugo and Ashton Lansdell squared off, it all came down to the final batters. The Cardinals sent up Alana Snow, who stars for the Great Britain softball team, while the Cubs countered with Great Britain baseball player Ural Forbes.

Unfortunately for the Cardinals fans, Forbes went off. The catcher, who appeared in one game at the World Baseball Classic this spring, smashed 12 home runs and put up an astonishing 24,650 points to send the Cubs to the finals.

Semi-final 2: Yankees 42,800 - Red Sox 26,250

Once again, GB Baseball came through, even making up for the fact that the Red Sox had two former Major Leaguers in Jonny Gomes and Hanley Ramirez on their roster. Nick Swisher gave the Yankees an early lead over Gomes before softball star Erika Piancastelli -- who won the MVP Award at last year's HRDX event in London -- extended it. After Ramirez gave the Red Sox a slim lead in the final round, the Yankees' Alex Crosby came to the plate.

Crosby knows a few things about hitting walk-offs. The Great Britain star hit the game-winning sacrifice fly against Spain that sent England to its first-ever World Baseball Classic appearance this March.

With a little less pressure here, Crosby went off: The slugger blasted home run after home run, putting up 19,250 points to send the Yankees to the final.

Final: Cubs 52,250 - Yankees 52,000

The final swings may have belonged to Forbes, but Cubs fans can thank USWNT star Alex Hugo for this one. After Swisher and Piancastelli put up massive totals with their first two rounds, it would have been easy to write off Chicago. But Hugo -- who appeared in every Home Run Derby X event last season -- displayed all the skills that earned her All-Tournament and Most Valuable Player Awards at the 2019 Pan-American champions when the USA won gold.

Hugo hit nine home runs and put up a best-in-the-event 25,750 points to give the Cubs the lead.

After Crosby topped 18,000 points in his final set of swings, Forbes came to the plate needing over 15,000 points to deliver the victory to Chicago.

He made it look easy, not even requiring his full run of 20 swings. Relying on the target hit point multipliers while hitting plenty of his own home runs, Forbes put up 15,450 points to give the Cubs a walk-off HRDX title.

While there was a champagne celebration to come, Fowler knew the only real way to mark the victory. The Cubs outfielder led the London crowd in a rendition of Steve Goodman's classic "Go Cubs Go."