If the Houston Dynamo are able to reverse their two-goal deficit against the Seattle Sounders in the second leg of their conference final Thursday (10:30 pm ET | ESPN, ESPN Deportes, TSN 1, TVAS 2), they'd be the first team ever to overcome a two-goal deficit in a second leg on the road.

In fact, only two teams have ever overcome a two-goal deficit in the Audi MLS Cup Playoffs at the series midway point (since aggregate play began in 2003), and no one has done it since 2004.

"But what about Toronto FC?" you might ask. And it's a fair point. They achieved arguably an even more impressive feat in their conference semifinal last season against the Montreal Impact. After losing the first leg 3-2 in Montreal and falling behind 1-0 in the second leg, they pulled off an astonishing 5-2 win to take the aggregate series and secure the right to host MLS Cup 2016. They also trailed 3-0 at one point in the first leg. However, they were down only one goal after 90 minutes.

Here's a look at the two teams who actually did trail by two goals after Leg 1, only to leave Leg 2 victorious and moving on to the conference finals. For good measure, we'll also review last year's thrilling Eastern Conference final.

San Jose Earthquakes vs. LA Galaxy

Nov. 1 and Nov. 9, 2003

This Cali Clasico Western Conference Semifinal was one of the first aggregate series ever played, as MLS debuted the format during the 2003 season. And it remains one of the best.

After the Galaxy took a 2-0 home victory in the first leg, Carlos Ruiz and Peter Venegas struck inside the opening 15 minutes of the second leg at Spartan Stadium to make it 4-0 on aggregate.

But never fear: Jeff Agoos and Landon Donovan got the Quakes level by halftime. Jamil Walker scored in the 50th minute, Chris Roner's 90th minute goal equalized the aggregate score, before Rodrigo Faria scored a Golden Goal six minutes into the extra frame to seal a glorious fightback and 5-4 aggregate win. The Quakes would go on to take their second and most recent MLS Cup title.

Kansas City Wizards vs. San Jose Earthquakes

Oct. 24 and 30, 2004

For San Jose, the soccer gods gaveth and the soccer guides tooketh away.

After pulling off their miracle comeback a season earlier, the 'Quakes were on the wrong end in the Western Conference Semifinals a year later.

This time, they looked free and clear after pulling off a 2-0 home victory over the Kansas City Wizards. But Davy Arnaud and Jack Jewsbury had other ideas.

After Khari Stephenson opened the scoring, Arnaud leveled the tie in the 56th minute. Then Jewsbury struck the winner in the second minute of stoppage time, wrapping up a 3-2 aggregate win and sending a small but passionate crowd at Arrowhead Stadium into delirium.

The Wizards would also reach the MLS Cup final, but fell 3-2 to a D.C. United side that won its fourth title.

Toronto FC vs. Montreal Impact

Nov. 22 and 30, 2016

Toronto left the first leg of last year's Eastern Conference final against the Montreal Impact with two crucial away goals and only a one-goal deficit. But less than an hour into the first contest, it looked like things would be far worse for the Reds, who trailed 3-0 after Ambroise Oyongo's goal for Montreal in the 53rd minute.

But Jozy Altidore answered in the 68th minute and then Michael Bradley scored in the 73rd, drastically changing the tone of the tie.

That set up a memorable second leg, which finished 3-2 in Toronto's favor after 90 minutes to set up extra time. That's where Benoit Cheyrou and Tosaint Ricketts became cult heroes, hitting the net twice in three minutes to seal Toronto's first appearance in the MLS Cup Final.

That's where the magic ran out, though. Seattle finished the playoffs as champions after their dramatic win on penalties over Toronto in a frigid final.