The Cottagers are still not guaranteed survival - though they will be safe if west London neighbours Chelsea beat Aston Villa on Saturday.
Fulham finish their campaign with matches against Liverpool on Sunday, and Swansea on the final day.
"It was early April that we had 40 points; we had that point against Aston Villa (on April 13)," Jol said.
"I knew it was very important to be on 40 points, when you saw the schedule ahead of us with Chelsea and Arsenal, Newcastle, away games, Everton.
"Of course, you can imagine we were a bit concerned, but the 40 points gave us a bit of a cushion.
"It still is a little bit of a cushion, but mathematically we're still not safe yet.
"We will focus on ourselves to try to get a result to be safe. The Wigan result helped and of course we need a result, but you depend on other games as well.
"We will look at other results and even when the results are going for us we have to try to finish the season on a very good note."
Jol is expected to perform major surgery on his squad this summer - a number of players will be out of contract or returning to their parent clubs after loan deals expire.
One loan star he wants to stay is Cologne right-back Sascha Riether.
"Sascha is my right-back and if he's fit he will play," said Jol. "Sascha was one of the better players this season. Of course we would like to keep him."
Jol says striker Dimitar Berbatov will also be staying: "That is not the worry I've got. He's got another year on his contract. That is not a concern at all.
"You need a lot of money to buy four or five players. If eight or nine or 10 players are leaving a club, you need at least five or six to come in.
"Hopefully we're able to do that. Otherwise we have to be very creative again."