Leigh Griffiths, Celtic's two-goal hero against Malmo, admitted his team face a tough task if they are to reach the Champions League group stages.
The lively forward scored twice in the first leg of the play-off round but that feat was matched by Jo Inge Berget as the match finished 3-2 to the Scots.
"At 3-1 we were still in command of the tie," said Griffiths, 25.
"At 3-2 it's difficult. We're still in front but we need to be very wary of Malmo's counter-attack."
Berget's second goal, five minutes into injury time, meant there were "mixed emotions in the dressing room" after the game, according to Griffiths.
The former Hibernian and Wolves forward was chosen by manager Ronnie Deila as Celtic's sole striker ahead of Nadir Ciftci for the first time in European games this season and scored in each half.
"I got the nod and after three minutes I've repaid the manager," he continued.
"We controlled most of the game and it was difficult to lose two away goals.
"I don't know where the referee's got five minutes (of injury time) from, it's beyond me.
"The corner came in and it's just a lack of concentration at the back and somebody's let their man go and Jo's put it away.
"Malmo have still got to come out and attack us. We're still in front so if we go over and get a draw we go through, but it's going to be difficult, the fans will get right behind them.
"We'll take a good support over there but hopefully we can do what we did to Qarabag."
Celtic goalie Craig Gordon said Berget's last-gasp strike was "a sore one to take" and accepted next Tuesday's return will be a challenge.
He said: "I think it'll be difficult with the two away goals. Both teams looked very capable of scoring goals when they went forward tonight so I'd expect another game similar across there.
"We've lost a few goals of late. Going back to last season we hardly lost any, especially domestically, so we have to get back to doing that and a very good time to start is in the second leg.
"We can do it. Malmo are a decent side, they carry a really good threat going forward, but we'll fancy our chances to score goals as well."
Midfielder Nir Bitton scored Celtic's second of the night, his header in the 10th minute adding to Griffiths's first. The Israeli is keen to see Celtic attack in Sweden.
"If we want to play Champions League, we need to go over there and we need to win the game," he said.
"We don't need to play for a draw because everybody saw who is the better team.
"We just need to play our game, do the same things we did in the first half and we will go to the Champions League."