Despite taking an early lead through the young winger, goals from Marc Laird, Anthony Straker and Kevan Hurst cancelled out Darikwa's fourth minute strike and sealed the victory for the away side.
Speaking after the game, the 21-year-old said: “It was good to get that start and nick a goal early on. We thought we could push on and hopefully get a few more goals.
“I just saw the play building up, Robbo got it and I know the quality he can put into the box so I’ve just gambled and it was a very good ball for an easy tap in.
“Unfortunately we couldn’t go through with the win, we’re out of the cup and we’re disappointed. For a footballer at any level if you’ve got the chance to play in the FA Cup it’s one of the biggest competitions in the world so it’s disappointing to get knocked out of it.”
After going on an eight-game unbeaten streak, the FA Cup loss was Chesterfield's second consecutive defeat in all competitions and Darikwa spoke about the early season form that has set the bar so high for the club.
“With the start of the season we’ve had, we’ve set our standards. I don’t think it’s any secret that we haven’t been up to those standards for the last couple of games now," said the youngster before adding: “We take every game as it comes and we’re working hard to sort it all out.”
The Nottingham-born star hadn't featured in Chesterfield's three matches leading up to the Southend game but was voted Man of the Match after starting on Saturday.
He said: “There’s been a lot of stuff speculated about me and I just wanted to prove to everyone that I want to be a part of the club.
“I’m focused on my football now, that’s all I want to do and hopefully I can show that with more performances like this.”