"Whenever I go to the mound I think I'm going to have a good game," Hernandez said. "Sometimes [it's] bad. Sometimes [it's] good. I can't control that. Today, I threw strikes, kept the ball down and made a lot of ground balls."
The Rays (64-43) are 21-4 in July and have won 11 of their last 13 to remain in first place by a half-game over the Red Sox in the American League East.
With talk of the Rays temporarily moving to a four-man rotation, Hernandez let his pitching respond to the idea he would be the odd-man out.
Hernandez blanked the Diamondbacks through 8 2/3 innings before Eric Chavez hit a two-run homer. Martin Prado grounded out to Evan Longoria at third for the final out, and just like that, the Rays starters were doing their leap on the infield, a maneuver they execute after every complete game.
Hernandez's five-hitter gave the Rays their seventh complete game in July, the most by any team in a calendar month since the Phillies in May 1999, and the most by an AL team since the Yankees in August 1998.
"He was hitting his spots very well, and his changeup was really, really good today," catcher Jose Molina said. "Good command."
Rays manager Joe Maddon said Hernandez was "the sharpest he's been."
"All components," Maddon said. "Fastball. Even the velocity of the fastball he sustained at a high level. Great location. And the slider and the changeup.
"You look at the quality of the swings from the other team, they have a very good ballclub. And actually, they matched up pretty well against him tonight, according to what works. Taking all of that into consideration, you look at the quality of the swings on the other side. His stuff was good."
Hernandez had 15 groundouts on a night when he needed just 102 pitches for 27 outs.
"He kept the ball down, and we hit a ton of ground balls on him," D-backs manager Kirk Gibson said. "Offense was stagnant again tonight. It wasn't a surprise, we had a good idea how he was going to approach us. You had to be patient and try to get the ball up and get the ball up in the air, but he threw a good game. We were just unable to capitalize on anything at all."
Maddon noted the ground balls are what the Rays want from Hernandez.
"He puts the ball on the ground, we have to be in the right spots," Maddon said. "If we're in the right spots, this guy is going to pitch a lot of games like that."
Despite Hernandez's success, Maddon said the performance would not affect the team's decision on whether to go to a four-man rotation.
"We're still thinking different things," Maddon said. "Hopefully by tomorrow we'll be able to give you guys the rotation for the Giants series."
Desmond Jennings set the tone for the Rays' offense in the first, when he turned a single into a hustle double from the leadoff spot. Ben Zobrist singled home Jennings, and James Loney added an RBI double to put the Rays up 2-0.
"When you hit the baseball, you have to be thinking two from Jump Street, and Desmond's got that kind of speed," Maddon said.
Yunel Escobar hit his eighth home run of the season in the fourth, a solo shot, and a sacrifice fly in the sixth, and Zobrist added an RBI double in the eighth to give the Rays a 5-0 lead.
Tampa Bay had 10 hits and seven walks, but still only managed to go 2-for-14 with runners in scoring position.
"We hit some balls hard without much luck, and that could have put a different number on the scoreboard," Maddon said. "And then of course, it's still about runners in scoring position. We have to be a little more efficient there, but overall we have been hitting the ball better.
"We've been hitting the ball hard. Sometimes you're fortunate. Sometimes you're not so fortunate. But up and down the lineup, good offensive performance and once again a good defensive performance."
Tampa Bay is now 10-1 in Interleague Play this season.
"We have played well against the National League so far this year," Maddon said. "I want to see that trend continue. ... It'd be nice to keep this kind of trek intact."