Whilst championship leader Sebastian Vettel was the best of the rest behind qualifying kings Mercedes, who locked out the front row with Lewis Hamilton on pole, Alonso suffered his worst result of the season as he was only 10th quickest.
Already trailing Vettel by 36 points in the drivers' standings, the Spaniard can expect to fall further behind after Sunday's race unless good fortune comes his way.
With team-mate Felipe Massa down in 12th, Alonso said: "We have not been competitive all weekend, and it's not normal to see Ferrari out of Q3.
"We need to recover now as we can consider the worst Saturday of the season so far having never finished so far down.
"We've not improved the car enough in the last four to five races and although we have new parts, they've not worked as expected.
"We must react immediately to try and return to the form we showed at the start of the year because we definitely expected a lot more here.
"This is a track that suits our car's characteristics better than others.
"Even if the race will be an uphill struggle we are well aware how things can change during a race.
"We hope we can stage a good climb up the order and bring home as many points as possible."
Lotus' Kimi Raikkonen, who is 44 points adrift of Vettel in third in the standings, is only one place ahead of Alonso on the grid.
"We got pretty much all there was from the car today," said Raikkonen, who was 1.3secs down on Hamilton.
"It's not ideal as we'd like to be nearer the front of the grid, but it is what it is.
"We'll go into the race wanting to get a better result than we did in qualifying. Usually this is what happens for us and hopefully that is the case again tomorrow [Sunday]."