PHILADELPHIA -- An unexpected 26-minute delay prior to Friday's game gave Christian Walker some extra time to visit with family and friends alongside the D-backs' dugout at Citizens Bank Park.

Though first pitch was pushed back nearly a half-hour before Walker proceeded to strike out in each of his first three plate appearances, he eventually rewarded his fans who stuck it out by crushing a game-tying two-run homer in the ninth inning. It all went for naught, however, as the Phillies ultimately handed the D-backs a 7-6 walk-off loss in 11 innings.

• Box score

Ketel Marte, who came off the bench after leaving Thursday's game with right hip discomfort, hit a two-run shot of his own in the top of the 10th to give Arizona a 6-4 lead, only for Brad Miller to answer with a two-run homer off Tyler Clippard in the bottom half. Philadelphia delivered the decisive blow one inning later, when Jean Segura lined a walk-off single off Taylor Clarke down the right-field line.

“It hurts. Every loss hurts,” manager Torey Lovullo said. “I know that room is engaged and wanting to win baseball games. As long as we figure out how to get that frustration and turn it into growth, that's my main concern right now. But these types of games where you're ahead and you expect to win, you want to lock it down.”

Despite the loss, Walker’s big swing came on the heels of a four-hit game in Thursday's victory -- a performance that he credited to the homemade meatballs that his mom, Julie, delivered to the team prior to the series opener. Perhaps then, Friday's clutch homer can be chalked up to the latest pregame treat, again courtesy of Walker's mom: Cake pops.

Whatever the reason, Walker has certainly made an impression through the first two games at a ballpark located just 25 miles southeast of where he grew up.

Though the homecoming has certainly been special, Walker had been heating up long before the club's trip to Philadelphia. The veteran backstop is hitting .280 with a .379 on-base percentage, three home runs, 13 RBIs and an .833 OPS over 22 games in August. He's reached base safely in 20 of those 22 games -- and one of the two exceptions came in a contest in which he had just one at-bat as a pinch-hitter.

The key for Walker has been his pitch selection. His walk rate in August has jumped to 13.8% -- nearly double his 7.0% mark through July. Walker has worked 12 walks in just 87 August plate appearances after drawing only 18 walks in 258 plate appearances previously.

“You can see he's kind of taking this thing to the next level. He's been slugging the baseball and he's been getting on base,” Lovullo said. “It’s just selectivity -- it's a very simple solution. It's a hard game because you're always sped up and the road is meant to be bumpy, but … you've just got to be stubborn to the pitches you're looking for, and I think Walk's doing a good job of that right now.”

Though the D-backs were held scoreless through five innings by Phillies starter Aaron Nola, they finally broke through in the sixth. Josh Rojas hit an RBI triple to knock Nola from the game, then raced home on Josh VanMeter’s sacrifice fly to erase an early Bryce Harper two-run homer.

The bats again went quiet until the ninth, when Walker sent an opposite-field shot out of the deepest part of the park. Marte put to rest any lingering concerns about his hip when he sent a no-doubter into the bullpen one inning later.

“We did enough offensively to win this game,” Lovullo said. “We just couldn't close the deal.”

Staked to a two-run lead, Clippard struck out Didi Gregorius before leaving a sinker out over the middle of the plate for Miller, who swatted a game-tying homer off the facade of the second deck in right field.

“This one hurts. It's frustrating, man,” Clippard said. “Definitely felt like a game we should have won. We played well, I just didn't get it through the finish line.”

Though the latest hiccup from the bullpen wiped out the highlight homers from Walker and Marte, the D-backs are still 9-6 over their last 15 games. For Lovullo, however, he knows his club could just as easily be 10-5 during that stretch.

“Right now, it's tough to stomach. I'm feeling it, I know that,” Lovullo said. “But at some point tonight, I'll turn the page and make sure I'm ready, and I know the rest of the guys will do that, as well.”