Houston Dynamo FC and Columbus Crew became the final two teams to book their spots in the Conference Semifinals of the 2023 MLS Cup with now just eight teams remaining.
It was a war of attrition for Houston, as their Round 1 tie with Real Salt Lake went the distance, with the best-of-three series being decided via a penalty shootout in Game 3.
Columbus were also taken to a decisive third game in their series with Atlanta United FC, but a 4-2 victory for the Crew at Lower.com Field was enough to extend their season and send the 2018 MLS Cup winners crashing out.
The MLS Cup will now pause over the international break, with the Conference Semifinals, all of which will be played as one-off ties, taking place over the weekend of November 25th-26th.
Houston had looked well placed to progress for much of their series with Real Salt Lake, as after winning Game 1 on home field, the Dynamo then led in Game 2 only to be pegged back and subsequently beaten on penalties
That set up Saturday's decisive third and final match and again the Dynamo looked to be in control, with Corey Baird putting them in front after 28 minutes with his first postseason goal against his former club.
However, back came RSL, with Diego Luna grabbing an equaliser midway through the second half, which ultimately set up a second penalty shootout between these two sides in the space of five days.
It was 3-3 in the shootout after four penalties each, with Nelson Quinones having missed for Houston and Luna for Real Salt Lake, before Danny Musovski struck the post with RSL's fifth spot kick.
That handed Griffin Dorsey the chance to clinch the match and series for Houston, which he did, as Ben Olsen's side made it through to the Western Conference Semifinals for the first time since 2017.
Houston are the fourth seeds in the West and their reward for seeing off Real Salt Lake will be a home tie with the eighth-seeded Sporting Kansas City in the Conference Semifinals on November 26th.
Having come through the Wild Card series after beating the San Jose Earthquakes on penalties, SKC caused the shock of the first round, knocking out the top seeds in the West, St. Louis City SC, in just two games.
Both sides will see this as a great chance to advance through to the Conference Finals, with Houston +900 to win the MLS Cup and Sporting KC +1400.
The other Western Conference Semifinal will see the defending champions Los Angeles FC, who made light work of the Vancouver Whitecaps FC in Round 1, visit 2019 champions Seattle Sounders FC.
Seattle needed three games to edge past FC Dallas in their opening play-off tie, but they will have home advantage for this one and are +800 to win the MLS Cup, while LAFC are +300 to defend their crown.
Columbus may have lost Game 2 of their series with Atlanta on the road - a result that took this Round One matchup to a decider - but they would have always been confident of getting the job done on home soil at Lower.com Field.
That's because Columbus were on a 16-match unbeaten home run heading into Sunday's contest and they never looked in danger of missing out on number 17 as they raced into a 3-0 lead after 33 minutes thanks to goals from Darlington Nagbe, Malte Amundsen and Alexandru Mațan.
Recently-named MLS 2023 Newcomer of the Year Giorgos Giakoumakis did pull a goal back for Atlanta before the break, but Diego Rossi restored the Crew's three-goal cushion two minutes into the second half, making Xande Silva's strike soon after no more than a consolation as the match finished 4-2.
Unfortunately for the third-seeded Crew, they will not have home advantage for their Easter Conference Semifinal, as they will head to Orlando City SC on November 25th.
Orlando, second seeds in the East, recorded a pair of 1-0 victories over Nashville SC to advance through to the Semifinals and momentum could well be with the Lions, who are +650 to win the MLS Cup, as they are on a six-game winning streak.
Columbus are also +650 to go all the way and land their third MLS Cup, but Wilfried Nancy will know his side will need to be on top form to stop their in-form rivals.
The East's other semifinal is an intriguing one to say the least, as Supporters' Shield winners FC Cincinnati will host last season's beaten MLS Cup finalists Philadelphia Union.
The Union are aiming to right the wrongs of last season's heartbreaking defeat to LAFC in the final and they are +900 to go one better than last year after seeing off New England Revolution within two games in Round 1.
Cincinnati, meanwhile, eased past New York Red Bulls in their opening play-off series and they are the +250 favorites to be crowned MLS champions for the very first time.
Odds mentioned in this article were correct at the time of writing and are subject to change.