How much does Toronto's two-goal aggregate lead over Club America matter?

Joe Corona, Sebastian Giovinco - Toronto FC vs. Club America

Toronto FC won the first leg of their Concacaf Champions League semifinal series vs. Club América 3-1 on Tuesday, giving them a two-goal lead to protect in next week’s second leg in Mexico City.

Will it be enough?

In the aggregate-goals format, whoever scores more total goals over the 180 minutes of play will advance, with the first tiebreaker in this case being away goals, the one consolation for América as they aim to mount a comeback at Estadio Azteca, their imposing high-altitude home venue. Thus a 2-0 Leg 2 win for Las Aguilas (or any other clean-sheet victory by a greater margin) would be sufficient to advance to the CCL final, while an away goal for TFC would force América to win by more than two goals to move on.

Toronto are under no illusions about the magnitude of the task ahead of them at the Azteca, for decades a graveyard for squads visiting from overseas, in América’s club matches as well as the Mexican national team’s home World Cup qualifiers.

But CCL history suggests that the odds lean in the Canadians’ favor.

Since Concacaf rejiggered its international club competition from the old Champions Cup format to CCL in 2008, 17 teams have taken a multi-goal aggregate lead in knockout series via victories by two goals or more in the first leg. And 14 of them have successfully held their advantage to advance to the next round, including the most recent 13 teams in that situation.

So who has blown a two-goal lead? We have to go back to the earliest years of CCL to find them – and one was a Canadian side.

In 2009 the Montreal Impact, back then a member of the USL First Division, qualified for the inaugural edition of CCL as Canadian Championship winners and mounted a plucky run to the quarterfinals, where they met Santos Laguna. Montreal knocked off the Liga MX heavyweights 2-0 in front of more than 55,000 fans in the first leg at Olympic Stadium, only to fall 5-2 in a wild, end-to-end second leg at Estadio Corona in Torreon, with one Darwin Quintero scoring two injury-time goals to seal the incredible Santos comeback.

That same year, the USL’s Puerto Rico Islanders – competing in CCL via their third-place finish in the Caribbean championship tournament – seized a 2-0 lead over Cruz Azul in the first leg before losing 3-1 in Mexico City, then losing a penalty-kick shootout (CCL had not yet adopted the away-goals rule at that point).

And a year later, Honduran side Marathon beat Pumas UNAM 2-0 at home in Leg 1 of their quarterfinal matchup before Pumas blitzed them 6-1 in the thin air of Mexico's capital city in the return leg.