West Ham United Under-18s fell to a 1-0 FA Premier Academy League defeat by Portsmouth on Saturday.
The Hammers were beaten by a solitary goal scored by the home side ten minutes after half-time at Little Heath.
The loss came just three days after the U18s were beaten in heartbreaking circumstances at Chelsea on the FA Youth Cup fifth round, where the Hammers conceded a last-minute equaliser before being defeated 5-4 on penalties.
Academy Director Tony Carr MBE said West Ham had again had enough chances be victorious, only to come up short against Pompey.
"We had enough opportunities to have won it, funnily enough," said Carr. "It was a tired performance, as you might have expected after the boys played 120 minutes at Chelsea in midweek.
"It was one of those games and we had the chances to win it but didn't take them. They scored the only goal of the game when they broke away from our corner on the counter-attack.
"After they had gone ahead, Portsmouth defended for their lives for the rest of the game and we couldn't find our way through."
The U18s return to action at Ipswich Town on Saturday 25 February.
West Ham United U18s: Wootton, Hurley, Shaw, Young, Siafa, Powell (Miles), Vose, Ruddock, Turgott, Sadlier (Fanimo), E.Lee