The fifth-seeded Russian led the Spaniard 5-2 in the decider.
"The end of the set was a little bit crazy," Lopez said. "Honestly, I think I was lucky. I came back, I don't know how."
In the final, Lopez will face Andy Roddick, who beat third-seeded Novak Djokovic 7-6 (5), 6-3.
"I'm excited," said Roddick of his win. "I played well tonight and I
played the right way. I had to, otherwise I wasn't going to
The first set was tight with Djokovic matching Roddick's
serve and the American trading on equal terms in the rallies.
The only break point fell to Djokovic when he got to 40-15
while leading 2-1. But Roddick fired two big serves that Djokovic
was unable to play effectively.
Having lost the first set, Djokovic looked unlikely to turn
the match around in the second.
He fought off a break point when Roddick led 1-0 and another
at 2-1 and was broken for 5-3 after a backhand error.
"He wasn't missing at all in the first set," Roddick said.
"He wasn't missing serves and I couldn't get into his service
games. I definitely had to try to stay the course and try and
tough out some games before I got the momentum on my side there
in the tiebreak."
Djokovic knew Roddick felt comfortable on the surface, and
that made him uneasy.
"I was nervous from the start," Djokovic told reporters. "I
didn't return well, although of course considering he has the
strongest serve in tennis it's not that easy to get the rhythm.
"I had a couple of break points but he served out well so I
didn't use the opportunities that were given to me. That was the
difference," he added.
"It could have gone either way if I'd won that first set."
Lopez started the match badly, losing the opening three games. Ranked 41st, Lopez has struggled since losing the 2004 Dubai final to Roger Federer.
Davydenko blamed his defeat on fatigue and tactics.
"I tried to win from [the] baseline, but I can't," he said.
The Associated Press and Reuters contributed to this report.