With most of the UEFA Cup Round of 32 ties looking well balanced going into tonight's second-leg matches, extra time and penalties could come into play to decide which teams enter the last 16.
Seven of last week's 15 first-leg matches ended in parity, including four goalless draws, while the margin of victory in the other eight games played was, with just two exceptions, a single goal.
Valencia CF and PFC CSKA Moskva both won 2-0 at home, against FC Steaua Bucuresti and SL Benfica respectively, while the FK Austria Wien-Athletic Club Bilbao first leg was postponed.
Away goals rule
Should tonight's 90 minutes of action fail to separate sides, the away goals rule will come into force ie the team that scores more away goals qualifies for the next stage.
Penalties if necessary
If this fails to produce a winner, two 15-minute periods of extra time will be played, after which the away goals rule - taking into account all 210 minutes of the tie - can again be invoked. However, if no goals are scored in extra time, penalties will then determine the outcome.
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