There's nothing quite like the magic of the cup.
The chance for lower league sides to pit their wits against the big guns is one that doesn't come along too often. That's especially the case in the United States, where USL teams have no prospect of relegation.
But just because they don't have access to MLS, that doesn't mean USL can't compete and this year's US Open Cup proves it with two teams from the US second tier making it all the way to the quarter-finals.
Of course, there hasn't been a non-MLS winner of the Open Cup since 1999, but the further these USL teams go, the higher the chances get. And there will be some nervous MLS teams heading into the next round.
Here's the state of play after the round-of-16:
US Open Cup quarter-final draw and dates
- Sporting Kansas City vs Union Omaha
- New York Red Bulls vs NYCFC
- LA Galaxy vs Sacramento Republic
- Orlando City vs Nashville
All matches are slated to take place on Tuesday, June 21.
US Open Cup: How did the teams reach this stage?
1. Sporting Kansas City
Sporting KC entered at the fourth round stage and had to overturn a 2-0 deficit before beating FC Dallas 4-2 - their equalizer coming in the eighth minute of second-half stoppage time.
On Wednesday, a brace from Johnny Russell once again helped them come from behind against another Texas team, this time the Houston Dynamo.
A potential banana skin awaits them in the last eight...
2. Union Omaha
USL side Union Omaha will be SKC's quarter-final opponents.
After beating Des Moines Menace in the second round, the Owls have made MLS teams pay, beating the Chicago Fire on penalties and coming from 1-0 down to beat Minnesota United 2-1 - both away from home - either side of a 2-0 win vs Northern Colorado Hailstorm.
Union have only won one USL League One match from five so far this season, but are punishing MLS teams on the road. Will SKC be one step too far?
3. New York Red Bulls
The New York Red Bulls have never won the US Open Cup, but did make the final in 2017 and 2003 - the latter when they were known as the MetroStars.
They took another step closer to adding the Cup to their trophy haul with a 3-1 win over newbies Charlotte FC on Wednesday - that win coming after a 3-0 away thrashing of DC United and a hard-fought 2-1 win against Hartford Athletic.
To win the US Open Cup, the Red Bulls will have to make it past Hudson River derby rivals NYCFC in the next round.
The MLS Cup champions beat 2021 Supporters' Shield winners New England Revolution 1-0 in extra-time on Wednesday having seen off Rochester New York FC.
NYCFC now have the taste for silverware and the Open Cup would look nice sat between their MLS Cup and Eastern Conference Championship titles.
5. LA Galaxy
The LA Galaxy are two-time winners of the Open Cup but their last title came back in 2005. They haven't even reached the final since 2006.
But Greg Vanney will be quietly confident after Wednesday's 3-1 win over Trafico rivals LAFC - the first MLS team they've beaten on this run after wins against San Diego Loyal (1-0) and Cal United Strikers (3-2).
6. Sacramento Republic
The Sacramento Republic await LA in the last eight and although the MLS team will obviously be huge favorites, this is no gimme.
Fellow Californian MLS team San Jose Earthquakes fell to Sacramento 2-0 on Wednesday, after the USL Championship team beat Phoenix Rising (2-0), Central Valley Fuego (2-1), and Portland Timbers U23s (6-0) in previous rounds
7. Orlando City
The furthest Orlando City have ever gone in the Open Cup is the semi-finals in 2019, when they were beaten 2-0 by rivals and eventual winners Atlanta United.
The Lions are just one game away from equalling that finish after wins over the Tampa Bay Rowdies (2-1), Philadelphia Union (2-1), and Inter Miami - the latter on penalties following Wednesday's 1-1 extra-time draw.
8. Nashville SC
Nashville SC will be Orlando's opponents at Exploria Stadium next month.
Gary Smith's side are competing in the Open Cup for the first time after the tournament was suspended for two years due to the Coronavirus pandemic.
They've made a good start, pulling off a dramatic 3-2 win over southern rivals and holders Atlanta United in their first cup match at GEODIS Park, before edging past USL Championship high-flyers Louisville City with a 2-1 comeback win on Wednesday.