Guptill took just 35 balls to reach three figures, and almost single-handedly helped his side to a nine-wicket win.
The New Zealand opener hammered an incredible 19 boundaries – 12 fours and seven sixes – as Northamptonshire chased down 188 in just 13.1 overs.
Guptill put on 162 runs for the opening wicket with Joe Clarke (61* off 33) before eventually falling to Richard Gleeson, the medium pacer.
Nathan Buck and Seekkuge Prasanna felt the full fury of Guptill’s blade. Buck conceded 33 runs in 2.1 overs, while Seekkuge Prasanna, the Sri Lanka leg-spinner, was taken for as many runs in his two overs.
Guptill’s knock was behind only Andrew Symonds’s 34-ball century for Kent against Middlesex in 2004.
It was also the joint-fourth fastest T20 century. The 30-ball effort from Chris Gayle for Royal Challengers Bangalore against Pune Warriors in the IPL 2013 remains the quickest in T20 cricket.
Rishabh Pant scored a 32-ball ton for Delhi against Himachal Pradesh in the India’s domestic T20 competition, the Syed Mushtaq Ali Trophy, earlier this year, while India’s Rohit Sharma, the South African David Miller and Namibia’s Louis van der Westhuzien are among the fastest centurions in Twenty20 Internationals.