SAN DIEGO -- Brandon Pfaadt was aware of what he was doing. The D-backs’ rookie right-hander didn’t need to look up at the Petco Park scoreboard to realize there was a big fat zero in the hit column for the Padres.

Inning by inning, Pfaadt combined an up-in-the-zone, mid-90s fastball along with his sweeper to confound San Diego’s hitters. The only blemish on his line through six innings were two walks, one to Manny Machado in the fifth and another to Garrett Cooper in sixth.

D-backs manager Torey Lovullo knew what was going on as well, and as is typical for him in those situations, he started looking at Pfaadt’s pitch count to try to decide just how many pitches he would allow him to throw.

It became a moot point in the seventh when Juan Soto laced a one-out liner to center that hit off the bottom of the wall for a double in an eventual 4-0 loss for the D-backs on Friday night.

Lovullo let Pfaadt finish the seventh, and he exited the scoreless game having thrown a career-high 107 pitches.

“We feel like we have a chance against anybody with our lineup, but the way he pitched -- he had to dig deep there in the seventh,” Padres manager Bob Melvin said.

It was a yeoman’s effort, especially with Arizona’s bullpen still recovering from heavy usage earlier in the week at Colorado and facing the prospect of a doubleheader Saturday.

“He did an unbelievable job all night,” Lovullo said. “He was still throwing 94 mph all the way through his final pitches. He was very ready for this challenge and kept us in this game, and he did his job.”

It was quite a different outing from the last time Pfaadt faced the Padres, which was just five days ago. In that game, he allowed three runs in the first and nine hits total over 5 2/3 innings.

This time around, he used his fastball up in the zone more, where last time he relied on it more down in the zone. It was the continuation of good efforts from Pfaadt, who is 0-6 after a rough start to his big league career this year. The seven scoreless innings lowered his ERA to 6.13.

“Their guy pitched really good,” Melvin said. “Last time we scored three in the first off him and felt like we should have gotten more, but he was legit tonight. He’s got a good fastball that explodes at the top of the zone. He has a good sweeper. He’s a big prospect for them -- I know the numbers don’t look great, but there’s a reason why they really like him, and man, he showed it tonight.”

After winning the first game of the series Thursday night, the D-backs had a chance to inflict a real blow to the Padres’ postseason hopes. A win by Arizona would have put the D-backs five games up on San Diego.

Instead, that number is at three with a pair of games on Saturday to finish the series. The D-backs now sit two games behind the Reds and Marlins for the final NL Wild Card spot.

The game unraveled for the D-backs in the eighth, when reliever Miguel Castro allowed four runs, two of which came on a Ha-Seong Kim single and another two on a homer to center by Fernando Tatis Jr.

Castro has struggled of late while setup man Kevin Ginkel has been on a roll, but Lovullo said he liked the matchup of Castro against the bottom third of San Diego’s order. It just didn’t work out.

“Ginkel was an option,” Lovullo said. “If we were ahead, I was going to Ginkel. I've asked a lot of him and [closer Paul Sewald], so I thought the commitment for me was if we were winning, I was definitely gonna go ahead and use them, but you know, hindsight is 20/20.”