By FOX Sports staff
The defending champions, who entered Sunday's clash at the Queenstown Stadium with eight wins from their opening nine games, were slight favourites for the tie but were expected to be given a tough test by Patrick Vallee's charges.
And following a goalless first half, French midfielder Kamel Ramdani struck in the 68th minute with his sixth goal of the season to hand Tanjong Pagar all three points.
The result was also enough to take the Jaguars ahead of Albirex Niigata (S) and into second place on the table.
Sunday's other clash saw Warriors FC record an impressive 2-0 win over DPMM FC at the Sultan Hassanal Bolkiah National Stadium.
Japanese midfielder Shimpei Sakurada opened the scoring for the Warriors in the 72nd minute, before Mislav Karoglan added a second five minutes later to wrap up a much-needed victory for V. Selvaraj's charges.
Sunday's Great Eastern-YEO's S.League Results
Tanjong Pagar United 1-0 Tampines Rovers
DPMM FC 0-2 Warriors FC