The striker raced clear one-on-one to score the Seagulls' third goal in a 3-1 win at Port Vale on Saturday.
That secured a place in the last 16 and a home tie against Premier League side Hull City next month.
Jon told www.seagulls.co.uk: "It was amazing to score because as a striker you love to score goals and that is my job at the end of the day.
“I saw it was a loose kick from the keeper and Jake [Forster-Caskey] did very well. I just had to time my run, then I saw the keeper coming so I had to round him and take my time with it. You just have to make good contact and then it is definitely going in.
“I said to myself that I would run to the fans when I scored my first goal but I am just happy to contribute and also for the team to go through to the next round.”
Jon could well face his Spurs team-mate Jake Livermore in that tie - the midfielder was a late substitute as the Tigers avoided a potential upset by beating Southend United 2-0 at Roots Hall.
In the Championship, Bongani Khumalo helped Doncaster secure a 1-1 draw at Blackpool while in League One, Alex Pritchard played the full 90 minutes and was involved in the first goal as Swindon toppled Shrewsbury 3-1 at the County Ground. Unfortunately, Ryan Mason departed early through injury.
In La Liga, Yago Falque came on in the 85th minute as Rayo Vallecano were beaten 4-2 by high-flying Atletico Madrid.