Two years ago, almost to the day, Liverpool departed from Stamford Bridge with a priceless 0-0 draw from the sides' opening showdown.
It laid the foundations for that astonishing night at Anfield when they grabbed a 1-0 win in the return encounter to secure a place in the Champions League final.
Alonso has mixed emotions about that 2005 semi-final in west London.
A late booking, for what he claimed was a dive by Eidur Gudjohnsen, meant he was banned from that memorable second leg.
He then had to sit, watch and listen as a wall of noise from the Anfield fans carried their team to glory.
Now the Spanish midfielder insists: "We have done it once, we can do it again. We stopped Chelsea two years ago at this stage and took them back to Anfield where our fans were incredible."
Alonso's memories of the awful moment he saw a yellow card brandished as Gudjohnsen tumbled have not changed.
He said: "I did not touch the player, the replays showed that, and I felt so sad knowing I would miss the second leg."
Now Alonso is aiming to play a full part in helping to complete another odds-defying Liverpool triumph over Chelsea.
He said: "It is strange that we have been drawn again against them at the same stage, but it shows what very good shape English football is in.
"At the moment, the English league is probably the strongest in the world, certainly top in Europe.
"We know Chelsea very well, they know all about us, so it will be down to the smallest details because the clubs are so familiar with the style and tactics of the other.
"We are hoping again to get a good result at Stamford Bridge.
"We have done that away to Barcelona and PSV Eindhoven already this season in the knockout stages - it gave us the platform to finish the job at Anfield.
"Now we believe we can do it again in this semi-final. For us, a good result is to score. That may sound very simplistic, but to do that makes a lot of other things possible.
"Obviously, we would not want to concede many goals, but the priority is to score ourselves because that gives a team the upper hand when they play the second leg at home.
"That would be good for us. If we get the result we want at Chelsea, they will know they have to face our fans again at Anfield."
He added: "That can be hugely intimidating for anyone. I had to sit in the stand the last time it happened because of the yellow card and the one match suspension.
"I could not help my colleagues, but I was able to really experience the strength of Anfield and the fact that they [the fans] can be the 12th man for us.
"The noise and support that night was frightening.
"Our people can be very excited, very strong in their support. They were really behind us.
"I experienced that very special support and you could see how it lifted our own players and maybe had an effect on our opponents."
The 26 year-old added: "It is good that we play the first leg away.
"It gives us a chance to assess the situation, see what happens and then we will know what we must do in front of our own Anfield fans.
"The whole thing is very exciting, the prospect of a semi-final of such a great competition, and again against Chelsea who know we have beaten them before at this stage.
"Everyone is really focused on what we must do, and really looking forward to a repeat of 2005."