Additionally, a 10th century before the age of 25 would see him join an elite group of historical greats in Don Bradman, Sachin Tendulkar, Alastair Cook, Garry Sobers, Neil Harvey, Graeme Smith and Javed Miandad.
Williamson also made a noticeable move up the all-time New Zealand test runs list overnight, moving into 11th place. The right-hander surpassed Craig McMillan and Richard Hadlee overnight, and now just sits 204 runs behind the tenth-placed Chris Cairns.
A New Zealander hasn't recorded a century at Lord's since 2008, when Jacob Oram hit 101, while only Oram and Mark Richardson have raised their bats at the famous ground since the turn of the century.
Williamson will have a chance to join that elusive group tonight.
New Zealand's highest test averages:
1. Kane Williamson - 47.36 (72 innings)
2. John Reid - 46.28 (31 innings)
3. Ross Taylor - 45.86 (114 innings)
4. Martin Crowe - 45.36 (131 innings)
5. Mark Richardson - 44.77 (65 innings)
6. Glenn Turner - 44.64 (73 innings)
7. Andrew Jones - 44.27 (74 innings)
8. Jesse Ryder - 40.93 (33 innings)
9. Bert Sutcliffe - 40.10 (76 innings)
10. Stephen Fleming - 40.06 (189 innings)