4. Gael Fickou (France)
The Toulouse centre was 19 years and 317 days old when he scored the winning try for France in a 26-24 win over England in the 2014 Six Nations.
3. George North (Wales)
The Welsh winger was 19 years and 302 days old when he bulldozed his way over the line in a 23-21 win over Ireland with Wales securing the Grand Slam in 2012.