Boss Brendan Rodgers insists his Celtic side answered a big question about their mentality during a pulsating 5-2 win over Hapoel Be'er Sheva, which took the Parkhead club closer to the Champions League group stage.
The Scottish champions were cruising at the interval after hitman Leigh Griffiths struck with a header and a brilliant free-kick after attacking midfielder Tom Rogic opened the scoring in a thrilling play-off first leg at Celtic Park.
However, two strikes in two minutes after the break from Brazilian striker Lucio Maranhao and captain Maor Melikson had the Israeli side back in the game.
But Celtic steadied, rallied and goals from substitute Moussa Dembele and skipper Scott Brown restored the home side's three-goal advantage for the return game at the Turner stadium next Tuesday night.
Rodgers said: "It is a brilliant result for us. You would obviously prefer 3-0 but 5-2 really shows the level that the team played at in a European game where there is everything riding on it.
"We were excellent in the first half, we pressed them aggressively, created opportunities, scored three and maybe could have had more.
"We started the second half well, I was pleased, then we had a spell when we defended very poorly for 10-12 minutes and conceded two poor goals.
"We didn't reduce the space, there was a little bit of inexperience, and it goes to 3-2 quickly again and then there is a question asked of you.
"Before the game I mentioned about periods when you come under pressure and it is having those check points in place to stay calm, get control of the game and look to shift the momentum of the game.
"At 3-2, to then go and win the game 5-2, really shows that mental strength of the players as well as the quality.
"They are nowhere near the finished article yet but they look a really exciting team which is full of character."