Larsson's return following a premature international retirement has only added to Sweden's quiet optimism, helped by a record of beating Bulgaria seven times and drawing twice in their last nine meetings.
But they know that Bulgaria, who they beat in a third-place playoff at the World Cup 10 years ago, could secure their first victory over the Swedes since 1967.
"We must be controlled and sensible," said Sweden coach Lars Lagerback. "But we feel confident. We have prepared well, we have a good record against them and we are ambitious for this tournament.
"Henrik's return is a boost, too, just what we needed for this tournament."
It could be also that Larsson's experience and ability brings out the best in his striking partner Zlatan Ibrahimovic, whose height, strength and technical ability should perfectly complement the Celtic striker's skills.
Sweden believe Bulgaria's main threat comes from the creative passing of another Celtic player, midfielder Stilian Petrov, and the finishing of striker Dimitar Berbatov.
The Swedish defence has also been warned to beware of Berbatov's fondness for simulation and ability to trick defenders into challenges to win free kicks and penalties.
In a group also including Italy and Denmark, the Swedes are keen to claim a convincing opening win at the Jose Alvalade stadium to provide insurance against later problems in the group.
The Bulgarians, keen to develop a new generation of players after the passing of the Hristo Stoichkov era, have said they welcome the return of Larsson two years after he announced his retirement.
"It is good for football, all of football wins from his return," said Bulgaria coach Plamen Markov. "We know everything about the Swedish team and it's only to be expected they know almost everything about us."
Probable teams:
Sweden (4-4-2): 1-Andreas Isaksson; 2-Teddy Lucic, 3-Olof Mellberg, 15-Andreas Jakobsson, 5-Erik Edman; 21-Christian Wilhelmsson, 6-Tobias Linderoth, 16-Kim Kallstrom, 9-Fredrik Ljungberg; 10-Zlatan Ibrahimovic, 11-Henrik Larsson.
Bulgaria (4-4-1-1): 1-Zdravko Zdravkov; 7-Daniel Borimirov, 18-Predrag Pazhin, 3-Rosen Kirilov, 4-Ivailo Petkov; 13-Georgi Peev, 15-Marian Hristov, 19-Stilian Petrov, 17-Martin Petrov; 21-Zoran Jankovic; 9-Dimitar Berbatov.
Referee: Mike Riley (England)
Linesmen: Philip Sharp (England), Glenn Turner (England)
