The most exciting second leg matches in European knock out competition will follow a home 0-0 or 2-1 result, according to analysis of 6,975 Champions League and Europa League games.

Professor David Forrest, a football industry expert in the University of Liverpool’s Management School, assessed the outcome of every two-legged match in European competition from the birth of the away goals rule in the 1960s right up to the 2012/13 season.

Home advantage?

Professor Forrest was seeking to establish how satisfied a club should be with a given first leg outcome, and what the prospects for progression would be against a series of variables, including relative club and country strength.

He found that the advantage conferred on playing at home has diminished significantly over the 60 years of European competition, with 56% of home legs won between 1965 and 1981 reducing to 46% between 1997 and 2013.

Despite this, he found that ‘home-first’ clubs have become “more adept at converting any given scoreline to success over the whole tie”.

“Suspense will be maximised where the first-leg score is 0-0 or 2-1, but we found that a 1-0 home win for an underdog gave it a better-than-evens chance of causing an upset in the tie as whole”

Part of the reason for this is the adoption of a more defensive approach in home-first legs, as Professor Forrest found the impact of conceding an away goal in the first leg “proves to be severe”.

So, where a 1-0 result in the period 1965-1981 was considered the “closest to a neutral result”, by the period 1997-2013 “a first-leg win by 1-0 must be considered a good result for the home-first club, giving it almost a 2-to-1 advantage going into the second leg”.

Professor Forrest said: “Similarly, winning by one goal but conceding an away goal had to be considered a poor result for the home-first club in the first data period, but it is now the closest to being neutral: it is the result which yields the most balanced contest going into the second leg.

“The damage inflicted on the home-first club by an away goal in the first leg proves to be severe. A score draw, compared to a 0-0 draw, leaves the then visiting club an underdog by nearly 3-to-1 concerning progression to the next stage.”

Parity

Professor Forrest found that a 0-0 first-leg draw or 2-1 first leg win for the home team are “the only two results which leave anything approaching parity between the two teams following the first leg”.

Professor Forrest said: “Suspense will be maximised where the first-leg score is 0-0 or 2-1, if all the matches are between average strength teams. But we found that a 1-0 home win for an underdog gave it a better-than-evens chance of causing an upset in the tie as whole.

“In this circumstance, the fans may find it worthwhile to travel and the clubs to field full-strength teams!”

What is a good result in the first leg of a two-legged football match? was published in the European Journal of Operational Research. The report was co-authored by Dr Juan De Dios Tena Horrillo from the University of Liverpool’s Management School and Dr Ramon Flores and Cesar de Pablo from Universidad Carlos III, Madrid.

