The German made contact with Ricciardo's Red Bull vehicle at turn 13 as the pair were battling for fourth place, before spinning out and dropping into 15th.
Raikonnen, meanwhile, wins his first Grand Prix since 2013 in Australia - ended a run of 113 races without a win - while Hamilton and Vettel's battle will continue in Mexico where he needs to outscore the German by just five points.
"Considering there's been some Q3s in the past races where I have had to bail out, the second one as it was not good enough - I was very strict with myself today, to pull through the second lap". The fact he didn't is a testimony to how good the race that followed was, especially the performances of the two men who eat him to victory in Austin.
Belgian Stoffel Vandoorne qualified last but will move up the grid thanks to engine penalties applied to the Toro Rossos of Pierre Gasly and Brendon Hartley, who will go to the back of the field. We have got to make sure we come here and raise the bar again.
I'll be here for the next few hours for all the build-up, live updates and reaction from the 2018 US Grand Prix.
"So I am just focusing on driving the best that I've driven all year long and that we get the auto where we need to get it".
Vettel qualified second, and just 0.061 slower than Hamilton, but has a three-place grid drop after failing to slow sufficiently while red flags were being waved in Friday practice.
If Hamilton wins then Vettel must finish second to keep the title race alive (well, more realistically it's on life support.) until Mexico next week.
It took him until Lap 51 to get within one second of Verstappen and gain DRS, but the Dutchman was likewise closely tailing Raikkonen in the lead, neutralizing the advantage.
A megastar-in-waiting: The build-up to the weekend was all about how Hamilton was on the cusp of winning a fifth championship. Hamilton leads Vettel by 67 points and any result Sunday that puts him eight or more points ahead of Vettel clinches the title.
Following the Japanese Grand Prix, Hamilton posted on Instagram to defend Vettel, claiming he had been the subject of unfair criticism after a series of mistakes in recent races.