The youngster is hoping to get another chance after a promising start to his senior career at Spurs - his debut at Portsmouth and the games against Charlton, Palace and Birmingham.
Jacko played in a less familiar left-back role against Birmingham with Mauricio Taricco suspended but, with Tano back, and Simon Davies flying again after injury, he was on the bench at Leeds on Saturday.
Now it's up to him to force his way back. "As a young player, my performances will be scrutinised," said Jacko at Spurs Lodge.
"I know if I'm not doing the business every week, I won't be in the team, won't be in the squad, simple as that.
"As long as I'm in there and doing well then there is no reason not to continue playing me but once those performances dip, it will be picked up on and I won't be in the team the next week. It's up to me to keep my place."
He can take heart from Rohan Ricketts this season. He got his surprise chance on the opening day and, although not starting, he been in the squad since and now racked up 22 appearances.
"Rohan got his chance, did well and has the rewards now," said Jacko. "He's been involved all season. It shows if you can get in there, keep your form up and get a run of games your position at the club can change.
"I want to be involved in every game now. Once you get a taste of that type of football, that's all you want to do."
John Jackson knows his every move on the park at first team level will be scrutinised as he bids for a regular place in the squad.