4. Neil Harvey - 24 years, 122 days
Former Australian great Neil Harvey is one of the finest left-handed batsmen to have represented his country in Test cricket. Harvey played 79 Tests in a career which spanned 15 years and managed to score more than 6000 runs at an average of over 48. This included 21 hundreds and 24 half-centuries.
Having made his debut for Australia at the age of 19, Neil Harvey achieved the milestone of scoring 10 centuries in his 24th Test. It was the final game of a 5-match series against South Africa and the Aussie batsman hit 205 in the first innings. At 24 years and 122 days, Harvey became the 2nd youngest batsman at the time to clinch this feat.