Sonny Bill predicts more misery for Wales as ranking humiliation awaits

Former All Blacks centre Sonny Bill Williams has flagged more misery for Wales in Round 4 of the Guinness Six Nations - predicting Italy will defeat Warren Gatland's men in Rome.

If Italy beats Wales, the Azzurri will become the higher-ranked of the two teams for the first time since February 2013.

A win for Italy will see them climb three places and enter the world's top 10 for the first time in a decade. Wales will drop out of the top 10 for the first time in defeat and could fall as low as 13th if the Azzurri beat them by a big enough margin. Alternatively, a Welsh victory will result in them climbing above Japan and into ninth place.

Williams clearly believes the former will happen, writing on Twitter: "Italy to beat wales [sic]. England gets the dub with the young gun Smith having a blinder. Ireland getting that grand slam [sic]."

Indeed Ireland will retain their top spot in the World Rugby rankings if they avoid a defeat against Scotland in the final fixture of the Guinness Six Nations at Murrayfield on Sunday, even if Les Bleus have won the previous day.

If France lose to England by more than 15 points at Twickenham on Saturday, and Ireland beat Scotland by at least the same margin, their lead could be extended to 3.09 points. In such a scenario, New Zealand and South Africa would move up one place, to second and third, with Fabien Galthie's men falling to fourth.

However, if France beats Steve Borthwick's side and Ireland loses, then France will replace Ireland as the world's best team. Ireland cannot drop any lower than second place, but in a best-case scenario, Les Bleus can lead the rankings by 1.40 points.

England could trade places with Scotland if they beat Les Bleus with any margin of victory or even a draw, as long as Scotland lose at home to Ireland the following day. However, if both England and Scotland win, England will only become the higher-ranked team if their victory is by more than 15 points and Scotland fails to match that margin.

South Africa is currently ranked fourth and has more than five points than fifth-ranked Scotland. Therefore, even with a maximum of 2.26 points on offer for a home win, Scotland cannot improve on fifth place. Meanwhile, England is guaranteed to retain the sixth place regardless of the result against France.