Phase 1: Preliminary Round and Phase 3: Elimination Round • Greater aggregate number of away goals scored in regulation time in the two matches (excluding any goals scored in overtime) • Greater number of goals scored in the overtime periods at the end of the second match • Kicks from the Penalty Spot procedure (as per FIFA Laws of the Game)This is pulled directly from the competition rules on the CCL homepage. In plain English, just know that PKs are only necessary if the Sounders are trailing 1-0 at the end of regulation (which would mean the aggregate score is tied 1-1) and no one scores, or both teams score the same number of times, in overtime. If the Sounders are trailing 2-1 (or 3-2, 4-3, etc.) at the end of regulation (which means the aggregate would be tied 2-2) they would advance via tiebreaker without needing overtime. Hopefully that clears up any confusion.