Manchester United begin their Champions League defence at home to Villarreal on Wednesday and manager Alex Ferguson has set his side the target of becoming the first team to retain the title.
AC Milan were the last side to retain Europe's top trophy in 1990 but since the group stage format was introduced in 1992/93 nobody has matched them.
Complete coverage: Champions League 2008-09
"The fact that no club has won it in successive seasons shows just how hard it is to win the thing in the first place. But I really do think we've got a great chance," Ferguson said this week.
The Scot's optimism is based on the depth of his squad and the different options open to him as he plots a third Champions League success following on from 1999 and last season's final win over Chelsea.
The arrival of striker Dimitar Berbatov, a former Champions League finalist with Bayer Leverkusen, adds greatly to United's attacking threat.
However, they start their challenge from Group E short of the kind of form that helped them dominate last season.
The English and European champions have won just once this season and suffered a rare league defeat at Liverpool on Saturday, going down 2-1.
"We didn't have one performer on the pitch apart from possibly Rio Ferdinand. It was disappointing," Ferguson said.
"(But) you have to recover, that's the name of the game. It's the Champions League and we are in a good group and I think we have a good chance of qualifying."
United also lost midfielder Michael Carrick at Anfield with an ankle injury and will be without Paul Scholes, who is suspended after his red card in the Super Cup final.
They could though be boosted by the return from injury of Cristiano Ronaldo, who may figure among the substitutes.
Ferguson knows not to take anything for granted against the Spaniards, who were the last team to take anything from Old Trafford in the Champions League when they drew 0-0 in the 2005/06 competition. United have won 12 straight home games in the competition since.
Villarreal secured their place in the group stage by finishing as runners-up to Real Madrid last season, their highest finish in the Primera Liga.
They laboured to a 1-1 draw away to Osasuna in their opening league fixture two weeks ago but were comfortable 1-0 winners at home to Deportivo Coruna on Sunday.
Coach Manuel Pellegrini is without both his leading scorers from last season -- Turkey striker Nihat Kahveci and former United forward Giuseppe Rossi, who both have thigh problems.
"Without doubt the victory and the performance against Depor will give us more confidence for the trip to Manchester," Pellegrini said.
"We have a tough start, against the champions in their stadium, but we are also an important side and should go out looking for the win."
1-Edwin Van der Sar, 6-Wes Brown, 5-Rio Ferdinand, 15-Nemanja Vidic, 3-Patrice Evra, 24-Darren Fletcher, 8-Anderson, 4-Owen Hargreaves, 17- Nani, 10-Wayne Rooney, 9-Dimitar Berbatov.
13-Diego Lopez; 17-Javi Venta, 2-Gonzalo Rodriguez, Diego Godin, 5-Joan Capdevila; 8-Santi Cazorla, 19-Marcos Senna, 6-Sebastian Eguren, 11-Ariel Ibagaza; 9-Guillermo Franco, 16-Joseba Llorente.
Referee: Wolfgang Stark (Germany)
- Complete coverage: Champions League 2008-09