"One more win," Blake said. "The way I'm playing, I feel pretty good. I've never played this guy. Luckily, I got to see him play in doubles earlier this week. He got the better of me in the doubles, but hopefully I'll get a little revenge tomorrow."
He told the crowd after the match that he was pleased with his play.
"I played a really good tiebreaker, I felt," Blake said. "I couldn't have asked for a better end to it."
Blake, who lost in the semifinals last year, ran around his backhand to nail a forehand down the line out of Hernandez's reach to end the match.
The 28-year-old Blake beat Hernandez in two sets in their only other match. But that was on a hard court last year in Switzerland.
The American will play another clay-court specialist, seventh-seeded Marcel Granollers-Pujol of Spain, who took out unseeded Wayne Odesnik 3-6, 7-5, 6-3.
Blake said he probably won't change his tactics for the final.
"I'm going to try to take it early and not get into the kind of general clay-court battle of moving as far back as I can and just rolling it high and starting the point," Blake said. "I want to start the point with my advantage and taking it to them."
Blake broke Hernandez in the fourth game of the first set. How well the American returned in that game caught the Spaniard off guard.
"He give me four winners on my first serve," the 30-year-old Hernandez said. "I didn't play well today. I couldn't put in the first serve and that the reason that he returned pretty fast and pretty good to me."
The two players traded breaks in the final set. Hernandez broke Blake at 15 in the second game when the American missed a forehand volley long off a let cord on Hernandez's crosscourt passing shot.
Blake broke back three games later to get back on serve when he hit an inside-out forehand to pass the Spaniard.
It didn't hurt that Hernandez double-faulted twice in that game. But Blake's game plan is typically to hit out on his returns.
"That's kind of my plan a lot of times -- to take chances on people's serve. I can return well enough to put pressure on guys when they're serving. Even when they're serving pretty well, I can take that weapon away from them, and I did that early and made him a little tentative on his serve."
Hernandez got up 15-40 in the next game but Blake hung on to win his serve, finishing it on a running forehand crosscourt winner that the Spaniard could not reach.
Granollers-Pujol fought off two match points in his second set -- one on his own serve when he was down 5-3 and one in the next game on the American's serve.
"I feel very happy now and I feel very good," he said. Odesnik reached the semifinals after facing a couple of match points against him.
"It's disappointing (to have lost the semifinal) but at the same time, now I know how the guy I played yesterday must have felt, having one or two match points," he said.
Granollers-Pujol served better and played more aggressively as the match progressed, hitting on 65 percent of his first serves in the third set, compared to 50 percent in the first set. He repeatedly used deft drop shots off his backhand -- some from as far as 10 feet behind the baseline -- to wear down his opponent.
"I make the first and the second, and I saw that he wasn't running very good," Granollers-Pujol said. "And I start to make more and more."
Granollers-Pujol broke Odesnik's serve in the fourth game of the final set when Odesnik missed a drop shot wide after barely reaching one off the Spaniard's racket.
Before serving in the sixth game of the third set, the American called a trainer to stretch muscles in his left leg and his left hip.
Granollers-Pujol, ranked 84th, won on his second match point with an ace.
Both were playing in their first ATP semifinal.