Teams that won the first game 1-0 at home went through 65% of the time

The final whistle goes on the first of two cup games, and the home side is 1-0 up. The crowd drifts out, already talking about the next round. The question is old and simple: is that team through?

The analysis comes from the Soccer Addicted match archive. After the first game of a knockout match-up, where two teams face each other and the loser goes out, every fan asks the same thing. The games are called the first leg and the second, played at the stadium of the team that was away in the first. In general, the side with more goals over the two goes through.

To compare fairly, I sorted 5,027 match-ups, from 2004 to 2026, by first-leg score. Overall, 82% of sides that won the first leg went through. I start with the first leg at home, in their own stadium: of those who won 1-0, 65% went through (409 of 625). Now the first leg away, at the opponent's stadium: of those who won 1-0, 83% went through (348 of 419).

The count covers South America's top club competition, the Copa Libertadores, run by CONMEBOL, and three European ones: the Champions League, the Europa League and the Conference League. It also includes the Coppa Italia semi-finals, Italy's national cup. Of the 5,027, 3,678 are qualifying rounds, the stages that decide who gets into the competition proper.

The count lacks the European matches from February to May 2024, the end of the 2023/24 season, and part of the final stages in some editions, which decide the title. It was run on 19 October 2026. The total mixes qualifying rounds, final stages and the UEFA Cup's first round, a European competition that no longer exists. It describes what happened in these match-ups and predicts no other.

How many went through, score by score, at home and away

Away, none of the scores below left fewer than eight in ten sides going through.

At home, with a one-goal lead, 56% of those that conceded once went through, against 65% of those that did not. The table shows what happened together, not that the goal conceded knocked anyone out. In my reading, part of the home-away gap is that whoever wins away tends to be the better team.

A one-goal lead does not close the match-up

With a one-goal lead at home, whatever the score, 61% went through (683 of 1,120), and with two goals, 85% (505 of 592). The next table puts one goal, two goals and three or more side by side, at home and away.

At home, the first lead that tends to settle it is two goals, in the archive's match-ups. With three goals or more, more than nine in ten went through. In my reading, the one-goal lead is the one that fools people most, because it looks like a place in the next round and leaves almost four in ten by the roadside.

Away, with a one-goal lead, more went through: 86% (668 of 775). Even so, 107 went out. In the final stages only, the home figure drops a little and the away one stays almost the same, as the second row of the table shows. With a few hundred match-ups, that gap cannot be relied on.

Manchester City were on the wrong end of it in 2022. They beat Real Madrid 4-3 at home in the first leg of the Champions League semi-final, the round with four teams left. In the second leg, Real won 3-1 after extra time, the added period played in some cup games that end level. Real went through on aggregate, the combined score of the two games.

Liverpool know the feeling from March 2025. They won the first leg 1-0 away to Paris Saint-Germain in the Champions League round of sixteen. In the second leg, Paris won 1-0, so the aggregate was level. Paris went through on penalties, the shots, taken in turns, that settle a drawn game.

Without the away goals rule, the one-goal lead at home barely changed

Sides one goal up at home went through in 61% with the rule and 61% without it. The rule gave extra weight to a goal scored away when the aggregate was level. UEFA ended it on 24 June 2021, from the 2021/22 qualifying rounds. CONMEBOL dropped it in its 2022 competitions, according to newspapers. Left out: the Coppa Italia and the Libertadores finals, where the rule was not confirmed.

For away wins by one goal, the figure fell about 5 points without the rule, but, with a few hundred match-ups, that drop cannot be relied on. After a draw, the side with the home second leg went through far less often, from 67% to 56%. The bigger fall shows up where the away goal decided most, which fits the rule.

After a goalless draw, whoever played the second leg at home went through in 60%

After a goalless first leg, the side with the home second leg went through in 60% (278 of 463), the other side in 40% (185 of 463). The gap hides a trap. In the Copa Libertadores and some European rounds, the second leg at home goes to the side with the better record in the group stage. In the other European rounds, the order of the games is drawn.

To separate the stadium from the better-record side, I look at European rounds with the order of the games drawn and no away goals. There, whoever hosted the second leg went through in 49% (634 of 1,285). The likely range, the margin of sample luck, includes a coin toss. The stadium alone counts for little. The figure rises where away goals still counted and where the better-record side hosts the second leg.

What happened to sides in 4 first-leg situations

The archive has seen these four situations many times: a 2-1 win away, the same score lost at home, and a goalless draw seen from each side of the second leg. In the Copa Libertadores, if the aggregate ends level, the match-up goes to penalties. Since 2022, 32 of its 139 match-ups ended level, about one in four.

Each figure holds for all sides in the same situation, not for one club. Of those who won away, nine in ten went through; of those who lost at home, one in ten. After a goalless first leg, the 60% and 40% mix the stadium, the better-record side and the away goals rule, which applied until 2021. None of these figures says who goes through on a given night.

Every fan wants to take a 1-0 into the second leg. In the archive, the side that did went through 65% of the time at home and 83% away. In the second leg, the ball has not read any of these numbers.