PHOENIX -- If Tuesday night's game had happened in any season before this one, the Giants still would have lost 5-4 to the Arizona Diamondbacks. Right-hander Matt Cain still would have been disappointed by the way he couldn't hold an early four-run lead. The hitters still would have cringed over going eight straight scoreless innings in a hitter's haven.

But because this loss happened in 2014, the first year of replay challenges in Major League Baseball, the defeat came with an unexpected sting.

The Giants lost their first-ever review and thus also lost the opportunity to challenge a subsequent close play at the plate that gave the Diamondbacks a crucial run. Later, they lost the game.

"It's going to change the game, and this is going to be a critical part of the game," manager Bruce Bochy said of challenges. "I'm fine with (how it's set up right now), but we'll see how it goes. We're in the second game, so ask me a little deeper into the season, and I may say something different. But right now, I'm fine with it."

Bochy has long been an advocate of getting the call right, even if it means a delay for a video review, but the new rules left one loophole that came into play Tuesday. Managers get one challenge in the first seven innings but get a second shot only if they're right with their first one.

On two occasions in the first three innings -- a Joaquin Arias liner down the right-field line that was ruled foul and a bang-bang play at first on a Hunter Pence grounder -- Bochy jogged out to first base umpire Chris Guccione to discuss the call. As Bochy stalled, coach Shawon Dunston and batting practice pitcher Chad Chop studied two specialized screens in the clubhouse. Both times, the replay advisers decided that the call on the field would not be overturned.

An inning later, with the Giants leading 4-2 and Cain's pitch count rising too quickly, Bochy finally asked for a review. A.J. Pollock had singled but appeared to be picked off with two outs. The umpires ruled that the replay was inconclusive, and Pollock went to third one batter later when Gerardo Parra doubled.

With Aaron Hill at the plate, Cain crossed up Buster Posey, resulting in a ball that shot off Posey's glove and back to the screen. Cain raced to the plate and appeared to put the tag down on Pollock's heel, but for the second time in the inning, Pollock was ruled safe.

"He was out. I had him," said Cain, who passionately argued his case with home plate umpire Eric Cooper. "(Pollock) went through the top of my glove to go over it."

Television replays confirmed Cain's account, but the umpires couldn't look at them. The Giants were out of challenges.

Bochy said he didn't regret burning his challenge on a play that was not overturned.

"If we think the call is not right, we're going to challenge it," he said. "Now, that doesn't mean it's going to get overturned. In our eyes we thought he was out (on the pickoff), but unfortunately they're not all going to go your way. That's the gamble you take. Sure, there could be another one later, but you don't know that.

"Would I change anything? No."

Well, he might change some of the at-bats the Giants had after Pollock's run brought the Diamondbacks within one. The Giants had gone ahead on Brandon Belt's three-run homer in the first, but Wade Miley retired 15 straight after that, and the Giants couldn't bring a runner in from second in two of the final three innings.

Cain, meanwhile, needed 99 pitches to get through his five innings. The longest-tenured Giant said it's too soon to form a true opinion of replay.

But it's not too soon to know that the introduction of challenges will prove to be a new wrinkle for managers. Bochy, one of the game's best strategists, likely will need little time to adjust. As he recounted his first experience with replay -- which included two false alarms and one argument on a call he couldn't challenge -- Bochy repeatedly shrugged.

"That's what you call a 'hang-with-them,' " he said, smiling as he unleashed an old baseball colloquialism. "You can't do anything at that point because you already lost your challenge. This is how the system works."

On Tuesday, it didn't.

For more on the Giants, see Alex Pavlovic's Giants Extra blog at blogs.mercurynews.com/Giants. Follow him on Twitter at twitter.com/AlexPavlovic.

Wednesday's game
Giants (Tim Hudson 8-7 in 2013) at Arizona (Trevor Cahill 0-1), 6:40 p.m. CSNBA