There are some important changes to tournament rules for the European Rugby Champions Cup and European Rugby Challenge Cup from previous European seasons.Going into the key games in Rounds 5 and 6, organisers EPCR point out that if clubs in the same pool, or in different pools, finish on the same number of match points, the key change is that aggregate points difference from the matches between the clubs, or from the pool stage for clubs in different pools, takes precedence over the number of tries scored.   Pool winners The pool winner will be the club with the highest number of match points in each of the five pools. The best-placed runners-up will be the three clubs with the highest number of match points out of the five clubs that finish second in their respective pools. For the quarter-finals, the pool winners will be ranked 1 to 5 and the best-placed runners-up 6, 7 and 8 by reference to the number of match points earned.   Change to rules The rules for the Champions Cup and Challenge Cup feature a change to those used in previous European seasons in how to determine the order of clubs within a pool and how clubs are ranked for quarter-final purposes.   Clubs in the same pool If two or more clubs are equal on match points in the same pool, their ranking will be determined by the matches played between the relevant clubs as follows: (i) the club with the greater number of match points from those matches; or (ii) if equal, the club with the best aggregate points difference from those matches; or (iii) if equal, the club which has scored the most tries in those matches.   Clubs from different pools If ranking remains unresolved and/or if clubs have not played each other previously in the pool stage, ranking will be determined as follows: (i) the best aggregate points difference from the pool stage; or (ii) if equal, the number of tries scored in the pool stage; or (iii) if equal, the club with the fewest number of players suspended for incidents in the pool stage; or (iv) if equal, by drawing lots. Knockout stage The clubs ranked 1 to 4 will have home advantage for the quarter-finals as follows: Club 1 v Club 8, Club 2 v Club 7, Club 3 v Club 6, Club 4 v Club 5