The 33 year old Englishman produced arguably one of his finest days of golf, beating quarter-final opponent Ryan Moore and last-four rival Martin Kuchar en route to the final.
The Ryder Cup star had already impressed with a 5 and 4 win over Moore, before going on get the better of Kuchar 6 and 5.
He was six-up at the turn having birdied all but two of the first nine holes and, after going seven-up on the tenth, could even afford to drop two straight holes before an excellent approach shot on the 13th allowed him to pick up another birdie and take the match.
The score equalled the 6 and 5 win he achieved over Charley Hoffman in the first round.
"It was good," Donald, who only played 27 holes in the day, said.
"I didn't leave anything out there and I was pretty dominant. I was able to keep my opponents at bay.
"On a long day like this it was nice to get done early in both matches.
"I didn't know I could go to number three in the world, but that would be amazing. I've been playing consistently, but it's been a while since I've won over here (in America)."
Kuchar added of his opponent's performance: "There's no escaping Luke Donald. I played decent golf but he just tore me up."
Earlier in the day, Kuchar overcame Y E Yang 2 and 1, knocking out Graeme McDowell's conqueror in the process.
He had led by four at the turn but, after Yang dug in to win on the tenth and 13th holes, Kuchar held his nerve to chip onto the 17th green and then putt from three feet to win the match.
There was a good chance of the second all-European final in a row, as Germany's Martin Kaymer reached the turn all square with Bubba Watson.