Tuesday sees Helsingborg welcome Celtic for the first leg of their Champions League tie and home coach Age Hareide believes the key to success is to stop the visitors from scoring. The former Norway manager insists Celtic are favourites to reach the group stages but does not think his side have to take a lead to Glasgow for the return game to have a chance of upsetting the odds. Hareide pointed to the third qualifier against Slask Wroclaw, where Helsingborg went through 6-1 on aggregate after an impressive 3-0 first-leg win in Poland, when claiming a clean sheet against Neil Lennon's side was imperative. He said: "The most important thing is not to let Celtic score an away goal. That is the key to the tie. If they do score it will be very difficult for us. We don't necessarily need to take a lead to Parkhead. We had a good experience in Poland in the second qualifier, we did really well there and we defend well when we stick together. Celtic are favourites, they are a big club with good players. But expectations are high in Helsingborg with regards to Europe and the fans will be behind us at home. We have a good record there, I think we have only lost one game in two years, so we are strong and we played very well in our last home game (a 7-2 win over Kalmar). It will be an interesting tie. Tactics are important over two legs and things can change from one game to the other but we have to go into the game in a positive manner."Hareide insists nothing should be read into Saturday’s 2-1 defeat away to Elfsborg in the league. He said: "We played well in the first half and were winning 1-0 but we lost our legs a bit in the second half. We were playing on an artificial pitch which wasn't great. I also rested players for the game on Tuesday, some of them have played many games already this season. We will see who is fit today and get ready for Tuesday. We got the scouting report and we will make plans. I have seen Celtic against Helsinki and against Aberdeen and they are a good team, a hard-working side who are well organised and who can play different formations. Of course I know Thomas Rogne who is Norwegian and Georgios Samaras played for Greece against Norway when I was national team coach and we will have to watch him."