According to Cardiff City News, away goals do not count in match playoffs. If two teams come out as equals in two full-time encounters plus extra time, they have to square it out in post-match penalties.
The away goals rule is a common tie-breaker technique in association football. In a two-leg fixture, in which each team has a home game and an away game, the away goals rule is always the first tie-breaker if the game ends as a draw. However, the penalty rule is the ultimate tie-breaker if both teams have the same number of away goals after the two legs.
The away goals rule is not considered in match playoffs. A post-match penalty shootout is always the tie-breaker, regardless of the difference in away goals.