Published: 16:20, 10 November 2019
| Updated: 07:56, 11 November 2019
Andy Hessenthaler admitted he always fancied Dover's chances against Southend but said nothing because he wanted to keep a lid on expectations.
Substitute Ruel Sotiriou's stunning 84th minute strike was enough to give National League Whites victory over Sol Campbell's League 1 strugglers before a crowd of 1,754 at Crabble.
Dover boss Hessenthaler had watched the Shrimpers lose 4-1 at Portsmouth in midweek and saw enough then to give him plenty of encouragement ahead of the FA Cup first round tie.
He said: "I was confident but did not want to show that too much to the players because at the end of the day Southend are a League 1 side.
"I watched them with (assistant boss) Nicky Southall against Portsmouth and there wasn't too much in the game in the first half. It was very tight and Portsmouth scored just before half-time.
"Quietly we were confident if we started the game right.
"We had a game plan in terms of playing in their half.
"Yes it might have been a little bit direct but the quality of our balls going forward were excellent.
"At times we did get a little bit sloppy with that but when I came in last year we said we've got to play in their (the opposition) half more, and we did that and we got the results so maybe that's the way to go with this group of players."
Against a side which had won just once in 17 League 1 games Whites spent much of the game on the front foot.
However, a replay at Roots Hall looked likely until loan signing Sotiriou took matters into his own hands just three minutes after replacing the hard-working Steven Rigg
The 19-year-old Cypriot under-21 international was making his Whites debut after joining for a month from Leyton Orient.
Hessenthaler explained: "That was the worry, (the fact they had not scored) we had some good opportunities but did not really have that final bit of quality.
"That continued in the second half but we kept going and finally with the substitution, the young lad's come on and scored a fantastic goal.
"I've seen him in training the last few days and he's looked as bright as a button.
"It was a tough call that one because we've got Robert (Ratti) here as well.
"I've just said to him we've got faith in him as well but my gut was to go with Ruel and for me as manager it worked out.
"It was a wonderful day and a wonderful finish to the game, a great goal.
"We deserved to win over the 90 minutes I felt we probably should have scored more.
"It was a great atmosphere, the cameras were here for a reason and we've produced that, the players have produced that come 12 o'clock. I thought they were excellent from start to finish."
Whites are now just 90 minutes away from a place in the third round when clubs from the top two divisions come in.
The second round draw takes place on Monday evening and Hessenthaler admits it would be good to get the chance to perform at home again.
He said: "I think on that performance we'd like a home tie, it would be nice.
"If you're drawn away then it's got to be with one of the big guns who are in it at the moment.
"But let's just enjoy tonight and see what the draw brings.
"If we do get a home draw and perform like that then you never know we might end up in that third round."
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More by this authorMark Stokes