Paulo Sergio has nine Hearts players walking the suspension tightrope as they head into Sunday's Scottish Cup semi-final with Celtic. If any of captain Marius Zaliukas, Rudi Skacel, Andrew Driver, Darren Barr, Danny Grainger, Scott Robinson, David Templeton, Suso Santana and Jordan Morton pick up a yellow card in the game tomorrow they could miss the final. However Sergio has asked his players to hold nothing back against the SPL champions. Sergio said: "If they're going to be careful because of a yellow card, maybe they can't play at 100% and if we don't play at 100%, we're not going to be in the final. If I have one or two doing that and we win the game and go to the final, maybe they don't play the final, even if they don't pick up a yellow card. I'm not saying I want them to get a yellow card, but every single day when you go to do your job you have to give 100%." The Portuguese manager consider Hearts' task has been made all the harder since Celtic were beaten 1-0 by Kilmarnock in the Scottish Communities League Cup final last month. Celtic will be keen on lifting the double after they clinched the SPL title last weekend with a 6-0 win over the same opponents. Sergio went on: "I believe that defeat Celtic had is going to make our semi-final even harder. They already lost one cup and I'm sure they're going to be even more alert so that doesn't happen twice. They are favourites. We're going to be the first team to play against them as champions. They have had a fantastic season. They deserve this title. We know they are favourites. They have a fantastic squad, with a fantastic manager. We know it's going to be tough for us, but, like I've said before, maybe if we play 10 times against Celtic we can win one or two - I hope Sunday will be one of those." News of right-back Jamie Hamill picking up a cruciate knee ligament injury in training has hampered Sergio's options. The Tynecastle manager went on: "It's a pity. I'm very sad for him. He's one of those guys who every single day gives 100%. He's going to lose his opportunity to be on the pitch and he didn't deserve that." A number of of first-team regulars were missing from last week's 2-1 win at Dunfermline, but defender Andy Webster (thigh) should be back for Sunday. Templeton could also return for the first time since February following a groin problem. Sergio could even be tempted to give him a start as he said: "Templeton, after seven weeks, started working with the team on Monday. Physically he's ready. Maybe not to play 90 minutes. Sometimes I prefer to put him from the start and see if he can go or not." Sergio feels frustrated over the limit on substitutes allowed by the SFA's rule which restricts teams to five players on the substitutes' bench, rather than the usual seven. He said: "Just having four players and a goalkeeper on the bench - I don't see what Scottish football wins with this. It's very hard to pick a squad for a cup game here in Scotland." Webster hopes to be involved after missing the 2006 final following a contract dispute with owner Vladimir Romanov. The former Wigan and Rangers defender did not want to comment on that, but knows Celtic and, in particular strikers Anthony Stokes, Gary Hooper and Georgios Samaras, will keep him busy. Webster said: "Sunday's a massive challenge for us and everybody wants to get to a final. Celtic have shown great form throughout the season. They've been on an unbelievable run. We know it's going to be extremely difficult, but nobody gives you an easy passage to the final."