With record Spain scorer David Villa ruled out of the tournament, Torres is primed to put a lengthy period of poor form behind him, Reina, who played with the striker at Liverpool, told a news conference in Berne ahead of Wednesday's friendly against South Korea.
"It's been a while since I have seen him like this," Reina said.
"Physically, he is in good shape. Mentally he feels he is an important player in the national team, all the more so since Villa pulled out, and he relishes that role," he added.
"He feels comfortable and he looks switched on. Hopefully, he will have a good European Championships and Spain will feed off his goals."
Torres has had a torrid time since joining Chelsea in January 2011 but recently has started to look something like the player who struck fear into defences at club and international level and scored the brilliant goal that beat Germany in the Euro 2008 final in Vienna.
The 28-year-old known as "El Nino" (the kid) came off the bench to net the goal that killed off Barcelona in their Champions League semi-final second leg and looked sharp when thrown into the fray in the final against Bayern Munich, winning the corner that led to Didier Drogba's leveller.
He said this week he was determined to repay the faith shown in him by Spain coach Vicente del Bosque and with Villa sidelined by injury is likely to start for the world champions at the tournament in Poland and Ukraine starting next month.
"He seems less closed, with a positive attitude and the pleasure you get from coming to play for the national team," Del Bosque, who dropped Torres for a friendly against Venezuela in February, said.
"He has spirit and is in a very positive mood," added the former Real Madrid player and coach.
Spain begin their campaign to become the first country to win back-to-back continental titles with a World Cup in between against Italy on June 10, before meeting Group C rivals Ireland and Croatia.
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