Ben Polhill helped his Chichester braves dump Brighton out of the Sussex Trophy, then declared: "I always knew we could do it."
Chi bridged a gap of two divisions to win 24-23 in a thrilling first round tie at Oaklands Park on Sunday.
It was the most eye-catching result of a day which also saw second favourites Worthing and potential dark horses Eastbourne win through.
Brighton fielded a powerful line-up which included former Ireland prop Gary Halpin, who played the full 80 minutes and scored a try.
But Chi kept their noses in front and survived a late scare when Carwyn James was off target with a penalty which would have won the game for Brighton.
Skipper Polhill said: "We were always confident because we have been playing well and we have not lost at home yet.
"That confidence grew from the opening minutes when we saw they were not blasting us all over the park.
"But it was a bit worrying at the end. We were stood there waiting for their player to take the last kick of the game and we knew there was nothing we could do to stop him knocking us out of the cup.
"Fortunately it was a difficult kick and it fell short."
Wing Tim Rogers scored and also forced a penalty try when he was high tackled by Mark Gibb. Nick Stanton added four penalties and a conversion.
Brighton dominated in the scrum and forced a penalty try when their hosts repeatedly collapsed. James kicked two conversions and three penalties.
Coach Bert Merritt admitted: "I am very disappointed with it. We have got to look to rebuild for next season now."
Eastbourne also beat higher division opponents, but their 29-18 success at home to Crawley did not rank as a shock.
The teams are likely to swap divisions at the end of the season and Eastbourne have been playing great stuff lately.
Not this time, as Eastbourne's Graham Shiret admitted.
He said: "There was a lot of ball lost in the tackle and wrong options taken but we managed a few flashes of inspiration."
Tries from Matt Bremer, Thurston Yapp, Spencer Pullinger, Andy Hebron and Andy Moore, who added two conversions, set up a trip to Hove in the last eight.
Crawley led 10-0 early on with a Kelvin Cartwright try plus a conversion and penalty by Phil Howe. Alan Maybank went over late on.
Hove were 22-10 winners over visitors Bognor, who managed to waste 19 points in missed goal kicks.
Home skipper John Oades admitted his side rode their luck in that respect but said: "We scored the better tries and had the advantage territorially."
Back row men Darryl Elliot (2) and Kevin Long got the Hove tries with Martin Lovell converting one and adding two penalties.
Elliot and Andy Standing had spells in the sin bin and Bognor took full advantage to score through Des O'Connor and Andy Shipp.
Their skipper Karl Flynn said: "I can't say we played badly. We knew it would be a hard season but we have got a a lot of young lads coming through and now is the time to give them some experience."
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