While the Finn nibbled away at the Spaniard's lead, reducing it to 24 points with five races remaining, fortune again favoured Alonso when Colombian Juan Pablo Montoya [ Images ] spun on the penultimate lap.
Without that slip, McLaren would have been celebrating their first one-two in five years.
"The week was a little bit disappointing as we weren't competing with the McLarens, but the end was nice," said Alonso.
"I had some luck with Montoya's problems as well. But you know, sometimes you can make your own luck -- I kept the pressure on, and it paid off."
Raikkonen's commanding win from pole position at the new Istanbul track was his fifth success of the season and second in a row. He finished in one hour 24 minutes 34.454 seconds, 18.6 seconds ahead of Alonso.
Alonso, still comfortably on course to become Formula One's youngest champion at the age of 24, now has 95 points to Raikkonen's 71.
"It's not perfect but I couldn't do anything more," said Raikkonen. "I did the best I could. There's no way to score any more points if Alonso keeps finishing second."
It all went wrong for Montoya, struggling with a flat-spotted tyre, after he was hit from behind by Portuguese rookie Tiago Monteiro as he lapped the Jordan.
The Colombian finished third ahead of Renault's Italian Giancarlo Fisichella [ Images ].
"It was a bit of shame as we were looking good for the constructors' championship if we had had the one-two," said Montoya.
The undulating anti-clockwise track, likened to the Belgium's daunting Spa circuit by many, threw up plenty of overtaking for the estimated 90,000 strong crowd that included former world heavyweight champion Mike Tyson.
Schumacher, who had struggled in practice and was running 10th, was put out of the running by Williams's Australian Mark Webber [ Images ].
The two collided on lap 15 as Webber, apparently attempting to unlap himself after a pitstop to replace a punctured tyre, tried to squeeze past at the final corner.
Schumacher spun, pitted and resumed the race but then returned to the garages and got out of the car.
After a furious effort by the champion's mechanics, he eventually resumed 19 laps down in a bid to improve his qualifying position for Ferrari's home Italian Grand Prix on September 4 at Monza.
He finally retired with six laps to go and Ferrari failed to score any points for the third time this year.
"It was a race to forget," said team boss Jean Todt.
"In the past years, we have developed the nice tradition of winning races on a new track, but today that run has come to an end," he added.
Both Webber and Williams' team mate Nick Heidfeld [ Images ] retired after repeated rear tyre failures that supplier Michelin is investigating.
They were only bit players on a day that once again belonged to McLaren, who were left nine points adrift of Renault in the constructors' standings.
"It's a good result for us," said McLaren boss Ron Dennis. "We showed we can win the remaining races."
While Fisichella made the better start from the front row, leading Raikkonen into the first corner, the Finn sliced through with a breathtaking move at the end of the back straight to regain the lead on lap one.
On the next lap Renault instructed Alonso to pass his team mate: "Fernando, you're faster than Fisi, overtake him," the Spaniard was told on the team radio.
Montoya managed to get ahead at the pitstops, despite a mix-up that saw his refueller knocked to the ground when the Colombian was released too early.
Pos. Driver Time
1 Kimi Räikkönen 1:24:34.454
2 Fernando Alonso + 18.609
3 Juan Pablo Montoya + 19.635
4 Giancarlo Fisichella + 37.973
5 Jenson Button + 39.304
6 Jarn o Trulli + 55.420
7 David Coulthard + 1:09.296
8 Christian Klien + 1:11.622
9 Takuma Sato [ Images ] + 1:49.987
10 Rubens Barrichello [ Images ] + 1 lap
11 Jacques Villeneuve + 1 lap
12 Ralf Schumacher + 1 l ap
13 Robert Doornbos + 3 laps
14 Narain Karthikeyan [ Images ] + 3 laps
15 Tiago Monteiro + 3 laps
r Christijan Albers + 10 laps
r Michael Schumacher + 26 laps
r Nick Heidfeld + 29 laps
r Felipe Massa [ Images ] + 30 laps
r Mark Webber + 38 laps
Pos. Team Points
1 Renault 130
2 McLaren Mercedes [ Images ] 121
3 Ferrari 86
4 Toyota 71
5 Williams BMW [ Images ] 52
6 Red Bull Racing 27
7 BAR Honda 24
8 Sauber Petronas 14
9 Jordan 11
10 Minardi 7