PHOENIX -- The Chicago Cubs opened a three-game series against the Arizona Diamondbacks with a 5-4 loss in 13 innings at Chase Field on Friday.

How it happened: Nick Ahmed hit a walk-off RBI single in the bottom of the 13th inning off Zac Roscup. Ahmed also hit his first home run of the season off Jon Lester in the fifth inning. Chicago was one strike from winning in the 10th inning until Paul Goldschmidt hit a two-run home run off Hector Rondon to tie the game 4-4. Chicago scored a pair of runs in the top of the inning on RBI singles by Kris Bryant and Starlin Castro. Rondon came in for the save but couldn't preserve the lead.

What it means: Chicago moved to 2-2 on this six-game road trip and remains 3 1/2 games behind NL Central-leading St. Louis, which lost in Kansas City on Friday. Chicago lost for the second time this year after reaching a season-high six games above .500.

Quality start: Lester threw seven innings, allowing two earned runs on five hits and two walks while striking out four. The left-hander didn't figure in the decision and has not earned a loss in his past six starts dating back to April 19.

Ninth no-no: Reliever Justin Grimm didn't allow a run in the ninth inning, marking his seventh consecutive scoreless appearance (5.2 IP) since coming off the 15-day DL on May 6.

Homecoming: Catcher Miguel Montero pinch-hit in the ninth inning and walked. He received a nice ovation from the crowd when his name was announced. Montero played in Arizona from 2006-2014 and ranks among the D-Backs' all-time leaders in games (second, 906), RBIs (third, 448) and hits (third, 795).

K-ubs: Chicago batters struck out 11 times over the first nine innings.

Two picks: The Cubs picked off two Arizona runners. Tuffy Gosewisch was the first victim in the seventh inning when catcher David Ross made a nice throw to nab the Diamondbacks' catcher leaning. The second pickoff came with two outs in the 11th inning, on a 1-3-6 when Ahmed was tagged at second after he was caught trying to run, ending a potential scoring threat.

Up next: The Cubs play the second game of this three-game series at Arizona on Saturday with right-hander Jake Arrieta (4-4, 2.77 ERA) squaring off against Diamondbacks right-hander Rubby De La Rosa (4-2, 4.08) at 10:10 p.m. ET from Chase Field.