CHICAGO -- So many nights this season have seen the A’s offense string together late-inning rallies that result in comeback wins. But Monday’s fell just a few inches short.

Pinch-hitters Khris Davis and Chad Pinder extended the ninth by reaching base with two outs to bring the ideal batter to the plate in Marcus Semien, who had already homered twice. Semien nearly made it the first three-homer game of his career, but his deep drive off Cubs reliever David Phelps landed in Ian Happ’s glove just short of the wall in left-center and the A’s three-game winning streak was snapped with a 6-5 loss at Wrigley Field.

• Box score

The flyout nearly completed a furious rally that started with the A’s trailing by four in the eighth inning. The three-run frame featured Semien hitting his second homer of the night as part of back-to-back blasts with Nick Martini that made it a 6-5 game.

• Wrigley HR a stirring moment for Martini, family

“It’s not a surprise. That’s what they do and what they’ve done all year,” A’s manager Bob Melvin said of the heart shown by his club. “We put ourselves in a position where we were one groove away on the bat from going ahead. Proud of the fact that they kept working hard, even down four runs, to put us in a situation where we could win the game.”

Once the ninth inning was extended for Semien, there was only one feeling that came across the group of A’s players standing on the top rail of the dugout.

“We felt like we were going to tie this one up,” said A’s starter Chris Bassitt, who held Chicago to two runs over six innings. “Semien is one of our best players, and every time he comes to the plate, you expect something good to happen. It didn’t happen there, but he did more than his fair share today. He brought it.”

Semien’s sixth multihomer game of his career, and third this year, gave him 19 homers on the season, but it was not enough to overcome a bump in the road in the resurgence of Blake Treinen.

Tasked with holding a tie game as he entered the seventh in relief of Bassitt, Treinen lost it on six pitches. Pinch-hitter Ian Happ led off with a homer, sparking a four-run inning that saw Javier Baez blast his second homer of the night.

Much has been made about the rate at which balls are leaving the yard throughout the Major Leagues this season, and Monday provided more talking points, with seven home runs combined between the two clubs. Treinen said the home run surrendered to Happ on a 3-2 sinker was a no-doubter, which Statcast measured at an estimated 474 feet to right field, but he had some issues with the home run Baez hit into the Wrigley Field basket.

Feeling he got his slider close to where he wanted, Treinen said there were other factors that may have led to the home run.

“I feel like you gotta be careful how you choose your words nowadays. It’s not like it was the best pitch that I threw to Happ. He a hundred percent got that one,” Treinen said. “But the ballpark, in my opinion, played a factor with how good Baez got it. Maybe it’s the wind, maybe it’s the ball, but I didn’t feel like it was a swing that necessarily warrants a home run. Maybe a deep fly ball, and that’s not taking away credit from him, because he’s an incredible player.”

After losing the closer’s role in late June due to a poor start to the season, Treinen entered Monday night’s game with positive momentum. He’d allowed only one run in his previous eight outings, but the four runs allowed Monday equaled his total runs given up for the entire month of July. He also allowed two home runs in an outing for just the second time in his career.

“You play to your elements and tip your cap,” Treinen said. “It’s just frustrating to have tough results after Chris goes out there and throws six good innings, your offense scraps for runs late, and you sit there feeling like it’s your fault the game got away.”