Expected goals: Who are the biggest underperformers & overperformers in MLS?

Matchday 10 is in the books, providing a large enough sample size to better understand metrics like expected goals (xG) both for teams and players alike.

With data sourced from Opta, we've taken a closer look at the biggest underperformers and overperformers – as measured by xG – to understand who's sharp in front of goal, or maybe benefitting from an ounce of good luck.

For those unfamiliar, xG measures the quality of scoring chances by calculating how likely they are to result in a goal. Every chance is measured on a scale from zero (impossible to score) to one (expected to score every time), with on-field position and phase of play also factored in.

Note: In each table, scroll to the right to see all information.

Teams: Top 10 xG overperformers

St. Louis CITY SC opened the 2023 season with five straight wins, the best-ever start for an expansion team in MLS history. xG also indicates they were overperforming in the final third by a wide margin (8.47 goals), perhaps a testament to their high-pressing tactics under head coach Bradley Carnell.

Two other teams have overperformed their xG by 5.0+ goals: Eastern Conference foes Atlanta United (5.72) and Columbus Crew (5.06). The former, in part, is due to DPs Thiago Almada and Giorgos Giakoumakis defying statistical models, while the latter is more a byproduct of new coach Wilfried Nancy's positional-play-based system begetting chances (often with Lucas Zelarayán pulling the strings).

Teams: Top 10 xG underperformers

The Colorado Rapids' biggest critique is a lack of finishing touch in the final third, an observation that's supported by xG. Head coach Robin Fraser's team is the worst underperformer (-8.9) in the league, even as Diego Rubio leads the charge.

The LA Galaxy (-6.27) are second-from-bottom in the Western Conference and the New York Red Bulls (-6.25) are last in the Eastern Conference, struggling to complete chances the likes of Riqui Puig and Cristian Cásseres Jr. generate.

It's no surprise, either, that the league's worst offense is underperforming in drastic terms: Sporting Kansas City (-5.71) are winless through 10 matches and are finding lower-quality shots as of late.

Players: Top 10 xG overperformers

They're all in the Landon Donovan MLS MVP conversation, and it turns out xG overperformance is a trend among them.

LAFC forward Dénis Bouanga (4.0), San Jose Earthquakes winger Cristian Espinoza (2.75), Seattle Sounders FC forward Jordan Morris (2.68) and Atlanta United midfielder Thiago Almada (2.51) have all used their quality and hot streaks to exceed what xG predicts.

Also: Chicago Fire FC forward Kei Kamara (2.39), with 143 tallies, is two goals away from tying Landon Donovan for second in the league's all-time goals chart. At this rate, the veteran might leapfrog the American soccer legend sooner than expected.

Players: Top 10 xG underperformers

The expected progression from San Jose Earthquakes homegrown forward Cade Cowell (-2.84), at least as measured via goals, hasn't bore fruit through Matchday 10.

Sporting Kansas City midfielder Erik Thommy (-2.74) and FC Cincinnati midfielder Luciano Acosta (-2.24) have both missed from the penalty spot early on, plus seen their finishing boots elude them from open play. 

Vancouver Whitecaps FC striker Brian White (-2.69) is finding dangerous spots, but the final product proves slippery more often than not.