Alonso had booked a provisional slot in the final part of qualifying, but was eliminated when Force India's Nico Hulkenberg improved at the very end of Q2. But while it means the Spaniard will have started just one of the last eight Grands Prix from inside the top ten, he says that having free choice of starting tyre compound could prove more advantageous, given that McLaren are not fast enough to fight closer to the front at the Autodromo Hermanos Rodriguez.
"Yes! Fantastic!" Alonso said over the team radio after being informed he had booked P11, two places up on team mate Jenson Button.
Speaking to the media afterwards, he added: "It's not very nice to be happy for being 11th, but in the situation that we are in I think it's the best position for the start, on the clean side.
"We were not quick enough unfortunately. A couple of races ago we were fighting for seventh or eighth, now we are fighting for ninth or 10th, so 11th - being able to choose race strategy and the tyres - is the best option.
"Many things went our way today; we needed a bit of luck to get 11th position."
While Alonso expects to start on the soft tyres - the fastest strategy according to Pirelli is a two-stopper, using softs for the opening stints and mediums at the end - he said changing track conditions might yet throw up alternative options.
"I think so," he affirmed, when asked if he would start on softs. "The supersoft has been degrading a lot in the practice sessions, so it would be very risky to start with it tomorrow.
"But the track is improving and there's a better feeling with the tyres, so we'll see. We have that possibility that the top 10 don't have so we'll try to seize it."
While McLaren's form has varied race-to-race since the summer, Alonso has scored in five of the last seven races - including a season-best fifth place last weekend in Austin. As a result he now lies 10th in the championship, three points ahead of Williams' Felipe Massa and just two behind Force India's Nico Hulkenberg.