"Everyone can see there's a big difference to how we're playing now compared to when we last played in Eindhoven," said the Liverpool captain.
"We were more inconsistent as a team when we met them last time and had a lot of big players who weren't on form.
"If you look at us now, all the big names are performing well, whether it's Carragher, Reina or Alonso.
"It's the same for me. I was really frustrated at the beginning of the season because I was lacking energy in my game and felt lethargic physically and mentally.
"But since Christmas I've been feeling everything coming back. I'm training better and hopefully peaking at the right time because there are so many big games around the corner.
"We're all getting those feelings again as we did two years ago, but we're also telling ourselves to slow down. There's still a lot of work to do before we can think about Athens.
"But it's good we can watch the game tonight a bit more relaxed and enjoy it, even though I won't be thinking about the semi until the second leg is over.
"Last night was just as tough as Barcelona. Before that game, everyone was doubting us. This time it was reversed and we were expected to win.
"That brings a different type of demand. It's pleasing to perform when the pressure is on."