The 23-year-old Njoroge, who won the Hokkaido marathon in August, started to take the lead over Ethiopia’s Yakob Jarso shortly before the 37-kilometre point to cross the finishing line in two hours nine minutes 38 seconds.
“I’m very, very happy, because I ran under 2:10:00,” said Njoroge after beating his previous mark of 2:11:43 set when he finished fourth in Oita last year.
After all the pacesetters abandoned the race, Njoroge and Jarso were among the six men who formed a front-running group at the 34km mark.
Desta Gebrehiwet of Ethiopia and Japan’s Takehiro Arakawa were left behind as Njoroge, Jarso and Yuki Moriwaki of Japan took the lead after passing the 35km point.
Njorge moved up a gear after the 36km point, leaving Moriwaki behind and then Jarso one kilometre later.
Jarso eventually finished third in 2:11:13 as Ser-Od Bat-Ochir of Mongolia overtook him for second place in 2:11:05. Moriwaki was fifth in 2:11:51 behind compatriot Kohei Matsumura who clocked 2:11:18.