The new era at Tampines Rovers got off to an inauspicious start as they lost 1-3 to India's Mohun Bagan yesterday in the first preliminary round play-off of the Asian Football Confederation (AFC) Champions League.
The defeat means S-League side Tampines will now play in the second-tier AFC Cup.
Stags coach V Sundramoorthy was missing star attacker Jermaine Pennant - who was not registered in time - at the Salt Lake Stadium in Kolkata, but it was his defence which let him down.
Mohun Bagan, the Indian I-League champions, opened the scoring after just five minutes, when forward Jeje Lalpekhlua got ahead of Tampines defender Afiq Yunos to flick the ball home.
The home side then won a penalty after a clumsy challenge from South Korean defender Kwon Jun, but goalkeeper Izwan Mahbud saved from Cornell Glen.
But the Trinidad and Tobago striker bundled home a Sonny Norde cutback from close range in the 41st minute as the Tampines backline failed to mark its opponents tightly.
Midfielder Yasir Hanapi pulled one back two minutes later, powering home a header from a Hafiz Abu Sujad free kick.
The Stags poured forward in search of an equaliser in the second half, as Sundram brought on forward Jordan Webb for midfielder Izzdin Shafiq at the break.
Fazrul Nawaz thought he had levelled when he headed home a free- kick from Christopher van Huizen but it was ruled offside, although replays suggested otherwise.
With 10 minutes left, Yasir missed the best chance to level the scores. With only the goalkeeper to beat, he blazed the ball over.
That miss proved costly as Mohun's Japanese midfielder Katsumi Yusa dealt the final blow, poking home after a well-worked corner routine in the 83rd minute.