An apparent routine fly ball that dropped in. A pair of infield hits. A tying passed ball the catcher failed to hustle after.

The San Diego Padres had a most unusual rally against the Chicago Cubs.

Yonder Alonso's two-out fly ball to right field dropped in front of Julio Borbon for an RBI single that led to a four-run eighth inning and boosted the Padres over the Cubs 4-2 Thursday for a four-game series split.

"It was a little funky," Padres manager Bud Black said. "Good funky."

Travis Wood (2-2) retired his first 14 batters before Kyle Blanks singled, and he led 2-0 when Jesus Guzman reached on an infield single leading off the eighth. Blanks followed Guzman's hit with a walk, but Jedd Gyorko flied out and Nick Hundley fouled out.

Alonso, pinch hitting for Joe Thatcher, lofted a ball to right on the windy afternoon. Second baseman Darwin Barney backpedaled and Borbon sprinted in. Borbon called for the ball, Barney peeled off, and the ball fell just in front of Borbon's outstretched glove as Guzman scored.

"It's a ball that I felt I should've caught," Borbon said. "It's a matter of just that extra second of maybe Barney recognizing it and either calling me off or him being able to get out of the way. I felt like at the speed I was going in at, I would have been able to catch it if I wouldn't have seen him still there. He said that if he would've picked up the ball a 10th of a second earlier, he would've been able to call me off and maybe I'm veering off to the side."

Borbon entered at the start of the inning as a defensive replacement for Scott Hairston, who had put the Cubs ahead with a two-run homer in the seventh off Eric Stults. Borbon was making his third big league appearances in right, all since joining the Cubs on April 19.

Shawn Camp relieved, and his first pitch to Chris Denorfia was inside and bounced off the glove of Welington Castillo, who failed to hustle after it as the ball rebounded off the brick ball. Blanks at first hesitated, then ran home with the tying run.

"I want to apologize to my teammates for doing that, that's not going to happen anymore," Castillo said. "I feel like I lose the game. I'm the one that has to keep everyone in the game and I just got out of the game."

Denorfia walked, James Russell relieved and Everth Cabrera grounded a single to center for a 3-2 lead, San Diego's first lead since Tuesday. It was the Padres' only hard-hit ball of the inning.

Chase Headley followed with a slow roller past the mound toward second and reached on a run-scoring infield hit.

"It's one of those things where, regardless of what the situation is with the outs or what the score is, you can always take advantage of the mental lapses that go on on the field," Blanks said. "That's just a testament to nobody here giving up."

Thatcher (2-0) pitched one-third of an inning for the win. Huston Street allowed a two-out double to Nate Schierholtz in the ninth, then struck out pinch-hitter Luis Valbuena for his sixth save in six chances.

Wood (2-2) gave up three runs and four hits in 7 2-3 innings. He has won two of six starts despite a 2.50 ERA.

Stults allowed two runs and seven hits in 6 2-3 innings. He had been 0-3 with a 7.24 ERA at Wrigley Field.

On a raw afternoon, the gametime temperature was 45 — about 25 less than Wednesday — and the wind was blowing in from the north at 19 mph.

Chicago failed to take advantage of its early chances and went 0 for 7 with runners in scoring position.

Wood hit an inning-ending flyout with the bases loaded in the second, and Alfonso Soriano grounded into an inning-ending double play with two on in the third.

"Wood pitched really well today. In the first seven innings we didn't have too many good at-bats," Stults said. "But we were able to battle and then come up big in that eighth inning."