The talented left-sided player drilled in the cross for Helder Postiga to stab home his first goal just five minutes into his debut in the 2-0 friendly win at Stevenage Borough.
Jacko, still just 20, impressed in loan spells at Swindon Town and Colchester United last season but knows he has to do it on the home front this time around.
And the former England youth international has been doing plenty of work behind the scenes to give himself the best opportunity to progress.
He explained: "As I've got older every season has become more and more important but this is the most important going into the final year of my contract. It's all about trying to impress.
"I suppose it's make or break at Spurs. I've told myself that football has to come first and I've got to work hard because it could be my last shot at it.
"I'm probably fitter now than I've ever been in my career. I've worked hard throughout the summer, watched what I've been eating and looked after myself more than I ever have done.
"I've been conscious of my body and I feel better for it, certainly much slimmer and fitter. I've made a real effort to give myself the best opportunity."
As for last night's pre-season opener, Jacko reflected: "It was a decent start for me. I hadn't touched the ball in the first five minutes and I'm thinking 'what's going on here?' but literally my first touch I've set up the goal. It was nice for Helder to score his first goal and nice to get the assist. It's great to be involved so early and to be playing games again."
John Jackson will hope his first touch of 2003-04 paves the way for a season to remember - a season he admits could be 'make or break' for him at Spurs.