Alonso nudged Sebastian Vettel's Red Bull at Turn 2 on the opening lap, damaging the Ferrari's front wing.
The team left Alonso out, waiting for the chance to change to dry tyres, but the wing failed completely at the start of lap two, putting the Spaniard out.
"Today we had a good car and I don't think we were too far from Red Bull pace in the race," said Alonso when asked by AUTOSPORT how competitive his race could have been.
"They didn't have all the aces this weekend. No one was especially quick, so I think we could really have fought for the win.
"We are still missing some pace, but we have three weeks now to work and bring some new parts. Everyone will do it, but hopefully we can taker a bigger step than the others."
Alonso does not blame the team for leaving him out and believes he was unfortunate to retire.
"It was a very, very small touch, but enough to damage the front wing a lot," he said. "It was extremely bad luck in my opinion.
"We were constantly talking on the radio on the first lap. The car was behaving more or less well in the first two sectors.
"From the television the team saw damage, but we knew on lap three or four we would switch to dry tyres and if we could make it to then we could save 20-30 seconds in the race. To stop on lap one and lap three for the tyres is a little bit too much of a penalty.
"They said I didn't have the front wing performance I should expect, but to see how the problem was going to develop on the next lap.
"Unfortunately on the back straight the front wing dropped. At that point we were five seconds before the pit entry and we didn't make it.
"Looking now, after the incident, it was the wrong decision, but I think it was extremely unlucky - a combination of things that happened today.
"It can be the wrong decision or a good decision; you never know until you see afterwards."
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