The loss was the third in a row and dropped their record to 0-8 this year at PETCO Park with just one more game left here.
"We came out with a good attitude tonight," said D-backs interim manager Kirk Gibson, who had a pregame meeting with his club. "We played poorly. This kind of game is very humbling. We didn't pitch well, we made physical errors, we made mental errors, we didn't have a good approach when we needed it, and we really didn't give ourselves a chance to win. They made us pay for our mistakes."
The biggest mistake came with one out in the third and the bases loaded when Drew booted Chase Headley's routine ground ball for an error. Had Drew been able to come up with the ball, he likely would have been able to turn an inning-ending double play.
Instead, a run scored and everyone was safe, which set up a sacrifice fly by Jerry Hairston Jr. and a two-run single by Yorvit Torrealba.
"I think if you'd ask Stephen he'd give those home runs back to take the error away," Gibson said. "Stephen is as sure handed as any shortstop is in the league. One of those breaks and unfortunately we've made too many of those."
Drew did say he would gladly trade the homers for the error.
"I think I kind of overran it, tried to rush a little bit, and the next thing you know they have four unearned runs, so it's kind of an unfortunate thing," Drew said. "I take pride in my defense. It's one of those deals. It happens, but I'd [like to] take it back. You don't know what would happen with that double play if I get that right there and we come back in, so it's tough to swallow."
D-backs starter Joe Saunders also held himself accountable for the inning for not being able to pitch around the error.
If Drew made the play, "It's a different inning," Saunders said. "But that stuff's going to happen, you've got to turn the page quick. That's what makes good teams good teams, picking up your teammates. I could have done that there and controlled more of the damage."
Saunders (1-4) struggled with his command from the outset as he allowed nine runs (six earned) on eight hits over four innings. The left-hander walked three and fanned just one.
"I just don't think he had very good location," Gibson said. "He wasn't putting the ball where he wanted to."
After excelling in his first two starts after coming over from the Angels in a deal that involved Dan Haren, Saunders has allowed 19 earned runs in 22 innings.
"It's embarrassing to go out there and give up that many runs," Saunders said. "Hats off to them, they're a good ballclub, but the way I've been pitching I'm making them look like Babe Ruth up there. I've just got to make adjustments. I've got to start pitching better. This team made a trade for me, and I have to start proving my worth."
Drew led off the game with a homer, then doubled in his next two at-bats before homering to right in the seventh.
"You don't have nights like that too much and you're seeing the ball good and putting good swings on it," Drew said.
Wade LeBlanc (8-11) got the win for the Padres, allowing three runs on seven hits in 6 2/3 innings.