Tonight's losers at Lansdowne Road will definitely go out of the tournament without recourse to a play-off as the best third-placed team. The winners will finish second in Pool E and advance to the play-off in Lens against the best third-placed country from the five pools - Samoa or Argentina from Pool D.

If Argentina beat Japan tomorrow night, the top three teams will haveseven points and the criteria for the final standings in Pool D will be the number of points scored. As things stand, Wales (118) have scored more points than Samoa (97) and Argentina (50).

Thus, if Argentina beat Japan and score at least 48 points, they will move into the top two, and so tonight's winners at Lansdowne Road would then play Samoa in Lens. If Argentina win, but score fewer than 48 points, then the Pumas will be going to Lens.

Were Argentina to score 69 points, however, they would push Wales from top place: Samoa would still head to Lens, Argentina would face Australia in the quarter-final in Cardiff, and Wales would take on Scotland in a play-off in Edinburgh on Wednesday.