Pompey Academy suffered their first Youth Alliance League loss of the season, with a 2-0 defeat to Oxford at Copnor Road.
There was torrential rain and strong winds on the south coast, but Adam Smith netted twice in the first half to seal victory for the visitors.
Professional development phase coach Liam Daish said: “We struggled to cope with the conditions against a big, physical Oxford side.
“It was particularly difficult in the first half, when the wind was blowing against us and we didn’t adapt quicky enough.
“Their opener came from a long throw – which we knew was a major threat – and they got the first and second contact.
“We then conceded another poor goal and created our own problems really, trying to play in the wrong areas.
"We work hard in training to deal with different scenarios, but sometimes you need to play the game that’s in front of you."
“Oxford caught us out with their pressing and they were able to find a lot of joy during the transitions.
“The wind was in our favour during the second half and we caused a few problems, although not as many as we would have liked.
“We work hard in training to deal with different scenarios, but sometimes you need to play the game that’s in front of you.
“You need to be able to adapt to dealing with certain conditions and personnel, identify problems and cope with them.
“We saw the first team do exactly that against Sunderland at the weekend, so it’s about learning quickly to be able to change the momentum and put your opponents on the back foot.”
Pompey: Steward; Setters, Kaba, Traynor; Hughes, Simpson (Bosaka 69), Jewitt-White, Bridgman; Payce (Hurst 87); Kamavuako (Howell 62), Gifford