That's the best advice I can give Neil Lennon ahead of a game which could mark his greatest-ever achievement.
Considering the fact he has built this team almost from scratch, and using far fewer resources than previous managers or, indeed, counterparts at other clubs in this Champions League group, I have no hesitation in agreeing with Neil when he says getting to the knockout stage would top anything he has previously done.
He and his players have grown together in the past couple of years. Neil has proved himself an astute manager, and his men have shown they are comfortable at this level.
Now it's a case of holding their nerve to get what they deserve.
I can't see Benfica taking anything from the Nou Camp. Barcelona don't give anything away on their own patch, and consider losing an affront to their very existence.
So, it is down to Celtic to get the positive result they need, which is why I want to see them go for it from the very first whistle.
I believe that is the best way to counter any nerves and anxiety which could otherwise impact negatively on their performance.
By being positive in your approach, you remove Spartak's capacity to be a threat.
If Celtic can take an early lead, then build on that to get the job done, they can allow their focus to drift to what is happening in Barcelona – but not before.
I know from experience that is easier said than done.
In 1986, I took my Celtic side to Love Street to play St Mirren in the final league game of the season.
We knew we could still win the championship, but only if we scored a barrowload of goals and Hearts – who were leading the table – lost against Dundee at Dens Park.
I told my players only to focus on what they were doing, because, if they did not do their job, it did not matter what happened with Hearts.
The goals flew in early. At half-time, we were four ahead, but I was told, incorrectly, Hearts were also in front.
We went back out and kept hammering away at St Mirren in any case, and got five up within 10 minutes of the restart.
Suddenly, a roar started to build around the ground as news came through that Dundee had gone one up on Hearts.
A few minutes later, the same thing happened again, and we knew we had done it.
Despite all my years in the game, that crescendo of cheering really took me aback, and will live with me forever.
The point was that we did what we had to do, then could allow our focus to drift elsewhere.
Celtic have to follow the same plan.
Neil's players must not emerge with regret about not having done enough on the night, and the only way they can do that is by winning.