Oxfordshire coach John Brodley blamed costly errors as his side slipped to a 23-21 defeat against Durham in their championship opener at Gateshead.
But he refused to be too downbeat after a performance that showed plenty of positive signs.
Man-of-the-match Tom Johnson's try gave Oxon a 21-11 lead in the second half before Durham's strong finish dented the visitors' hopes.
Chinnor winger Charlie Oyebade proved a constant threat and scored Oxon's opening try, but it was his 66th minute sin-binning for persistent offside that was punished by Durham's resurgence.
Brodley said: "It was a game that we could and should have won and for that we have only ourselves to blame. Basic errors at crucial times cost us dear."
David Glendenning's conversion from Dan Oselton's try proved the difference for Durham in a game that saw sun and hail showers.
Brodley added: "I was proud of our overall performance against a team whose higher league experience was expected to hold sway.
"We have so much potential on which to build.
"We will re-group in the week, learn the lessons and look forward to next week's trip to Cumbria.
"Do not write us off for that trip to Twickenham."
Wins against Cumbria on Saturday and then at home to North Midlands on May 21 are vital if Oxon are to progress to Twickenham and Saturday saw many positive signs.
Fly half James Cathcart (Chinnor) had a good day with the boot and put Oxon 6-0 up with two well-struck penalties.
Durham full-back Glendenning reduced the arrears with a penalty of his own on 29 minutes before Oxon started to make more use of their back line.
The visitors felt they should have had a penalty try when Oyebade was impeded on the tryline, but had to make do with another three points from Cathcart.
Durham scored the game's first try in injury time through scrum-half Rob Stewart to leave the half time score 9-8 to Oxon.
Oxon lost hooker Alan Cawston with a shoulder injury and he was replaced by Simon Chadbone at the break, but the visitors still resumed strongly.
A thrilling passing movement on 45 minutes ended with Oyebade scoring and Cathcart converting the try.
Glendenning notched his second penalty to make it 16-11 before Oxon scrum-half Morgan Thompson's quick thinking set up Johnson's try.
Durham hit back with a push-over try and capitalised on their numerical advantage when replacement winger Oselton scored on 70 minutes and Glendenning converted.
Oxon: A Wallace (J Hewitt), L Gibson (A Noyce), M Nutt, C Shaw, C Oyebade, J Cathcart, M Thompson, S Matthews, A Cawston (S Chadbone), J Winpenny, T Cox, M Hutchins, A Milburn (P Soper), T Johnson, A Tibbetts (capt).
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