After four months off, Sadie Blakely's team were only back in action a week ago, with a cup victory over Kent Association United.
The visit to Leyton Orient was always going to be a tough test and with the game played on the club's main ground - where the men play in League Two - this was a great opportunity for both sides to experience a professional atmosphere, albeit with no fans allowed.
The game started brightly and Orient were straight on the front foot, delivering balls into the box that centre-back Sophie Phelps dealt with brilliantly.
Chichester and Selsey seemed a but nervous to start with and it took them a little while to get going. A free-kick outside the area allowed captain Megan Fox to deliver a ball that the Orient keeper spilled - and Phelps buried it to make it 1-0 on 12 minutes.
However Orient were playing well and causing their own problems, and were quickly back on level terms when a scramble in the box saw an Orient striker put the ball into an empty net for 1-1.
A busy first 20 minutes continued with a great strike from Fox going just wide. A strong challenge from Nicky Lake in central midfield saw the first card of the game.
Phelps had to come off injured and was replaced by Ariana Fleischman and Lake moved to centre-back. Chichester began to grow into the game and were in an around the Orient box with Tash Wild and Jane Yeates causing problems for their defence.
A lovely through ball from Yeates to Gemma Simonds saw her shot cannon off the post, but Wild was there to tap home for a 2-1 Chi lead before half-time. A dangerous ball into the Chichester box was punched away by Issy Foster in goal to keep the lead intact.
At the start of the second half Orient were awarded a penalty, much to the surprise of Chichester defender Amber Howden, who felt she got the ball.
But it was sent over the bar and Chi and Selsey still led.
Much of the second half was a scrappy affair with chances for either side few and far between. Both keepers made important saves with Foster making a cracking save to tip an Orient striker's shot over the bar on 78 minutes.
Orient piled on the pressure but the Chichester defence stood firm and booked themselves an away trip to West Ham in the fourth round this Sunday (April 18).
The winners of that game will face Manchester City Women or Aston Villa Women in round five.
The magic of the cup continues for Chi and Selsey...