Hosts Ratchaburi picked up three points following a convincing 3-1 victory over Sukhothai in a Thai League 1 encounter on Saturday night.
Njiva put Ratchaburi ahead in the 45th minute and grabbed his second of the night at the hour mark.
Sukhothai pulled one back in the 86th minute through Somkid Chamnarnsilp but Alvin Fortes was quick help the hosts regain their two-goal edge.
Also on Saturday night, Nakhon Pathom United ended a three-game winless streak, defeating Khon Kaen United 4-2.
Hosts Nakhon Pathom surged ahead only two minutes into match when Gaffar Durosinmi's shot was deflected into the goal by Khon Kaen goalkeeper Jirawat Wangtaphan.
Khon Kaen equalised through Jung Han-Cheol after 29 minutes but the home team were back in front four minutes later after a Lesley Ablorh header.
Thawin Butsombut levelled it at 2-2 on 62 minutes but Durosinmi netted twice more to secure three points for the home team.