How Champions League Knockout Ties Work: Aggregate, Extra Time and Penalties
How Champions League Knockout Ties Work: Aggregate Score, Extra Time and Penalties
A simple guide to first legs, second legs, aggregate scores, and what happens when a tie finishes level.
Champions League knockout matches can feel confusing if you're new to football. People talk about "first leg," "second leg," "aggregate score," "extra time," and "penalties," often in the same sentence.
The basic idea is simple: most knockout rounds are played over two matches, not one. Each team hosts once, and the combined score across both decides who goes through.
A knockout tie isn't decided by one match alone. In two-legged rounds, both results are added together before a winner is confirmed.
What is a knockout tie?
A knockout tie is a direct contest between two clubs — win and you advance, lose and your European season ends. In the Champions League's two-legged rounds, the two clubs meet twice: once at each side's home stadium.
First leg and second leg
The first leg is the opening match; the second leg is the return fixture played later, usually at the other club's ground. The first leg rarely settles things outright — it just sets the target, or leaves the tie level, before the second match.
That's why a team can lose the first leg and still go through overall — the tie isn't final until both matches are complete.
What does "aggregate score" mean?
Aggregate score is the combined score from both legs. For example:
- First leg: Team A wins 3–1
- Second leg: Team B wins 2–0
- Aggregate: Team A 3–3 Team B
Level on aggregate after both legs means the tie needs extra time, and possibly penalties, to find a winner.
During the second leg, track the aggregate score alongside the live score. A team can be winning on the night and still losing the tie overall.
Do away goals still count?
No. UEFA scrapped the away-goals rule from the 2021-22 season onward, across all its club competitions.1 Before that, a team level on aggregate could go through if they'd scored more goals away from home. Now, a level aggregate score simply means the tie moves to extra time — it no longer matters where each goal was scored.
For the full story on why UEFA made that change, see our piece on what happened to the away goals rule.
What happens if the aggregate score is level?
- Level on aggregate after the second leg → extra time begins
- Extra time is two 15-minute halves
- Still level after extra time → penalty shoot-out decides it
How penalty shoot-outs work
Each team takes alternating penalties, five per side in the first round. If one side has an unassailable lead before all ten kicks are taken, the shoot-out ends early. If scores are level after five each, it continues one kick at a time — sudden death — until there's a winner.
Is the final played over two legs?
No. The Champions League final is a single match at a neutral venue, with extra time and penalties available if scores are level after 90 minutes — but no second leg to come back in.
KickZone Take
Knockout ties sound complicated, but the mechanics are simple: add both legs' scores, see who has the higher total, and go to extra time and penalties only if it's level. With away goals gone, every tie now has to be settled directly on the pitch rather than by a technicality from an earlier leg.
Frequently Asked Questions
What does aggregate score mean?
The combined score from both legs of a two-legged knockout tie.
Do away goals count in the Champions League?
No — UEFA removed the away-goals rule from the 2021-22 season across all its club competitions.1
What happens if teams are level after both legs?
The tie goes to extra time; if still level, a penalty shoot-out decides the winner.
Is the final a two-legged tie?
No — it's a single match at a neutral venue.
Sources: 1. UEFA, abolition of the away goals rule in all UEFA club competitions.
