CHICAGO -- Ian Happ flipped his bat away, turned and began barking at home-plate umpire Vic Carapazza on Saturday afternoon. That earned the the infielder an ejection after Chicago's best window of opportunity against the Nationals had slammed shut.

There were a few chaotic aspects to the Cubs' 7-2 loss at Wrigley Field, and it is only right to note that the Nationals' offensive dominance has hardly slowed for more than a week now, but Saturday’s defeat can really be traced back to one moment in the fourth inning. That is when Happ -- pinch-hitting with the bases loaded -- was called out on strikes in the game's most critical at-bat.

• Box score

"He goes up there for a good pinch-hit, does it and does not get rewarded for it," Cubs manager Joe Maddon said. "That's the part that was frustrating about today."

That was just the cherry on top of a frustration sundae for the Cubs, who lost their first home series since May 24-26.

The typically sure-handed Anthony Rizzo made a pair of errors in the first two frames, and then the first baseman was out of the game due to mid-back tightness by the fifth. That hindered Maddon's in-game maneuvering, given that the Cubs are operating with a three-man bench and nine-man bullpen at the moment.

• Cubs' Players' Weekend nicknames

The Rizzo domino brought catcher Jonathan Lucroy into the game, leaving Addison Russell as the lone position player available in reserve for the final five frames. That created a situation where reliever Kyle Ryan was forced to hit in the sixth. He drew a walk, but the rousing cheers that stirred then turned to groans when he was later thrown out at third trying to advance on a wild pitch.

Beyond that, catcher Willson Contreras, who is on the injured list, was ejected between the fourth and fifth innings for yelling at the umpires from the Cubs' bench. While Contreras was being tossed by second-base umpire Hunter Wendelstedt, Maddon was actually in the tunnel reviewing a video clip of Happ's at-bat from the fourth.

"I was really, really trying hard to not get kicked out myself. And I accomplished that," Maddon said. "That was one of my things, because there was so much going on in that game with a short bench. So I said to myself, 'Don't do it.'"

Leading up to Happ's game-altering plate appearance, the Cubs were mounting a rally against Nationals starter Joe Ross.

Rizzo led off the home half of the fourth with a walk and then hustled to third on a ground-rule double down the right-field line by Javier Báez. Tony Kemp later drew a two-out walk out of the eighth spot in the lineup, making it decision time for Maddon. Starter José Quintana was not being hit hard, but Washington built a 5-1 lead behind seven singles and three walks against the lefty.

Maddon called upon Happ, who quickly fell into an 0-2 count against Ross. Then, the Cubs' infielder went to work for six pitches.

"He battled his butt off," said Kemp, who made three dazzling plays at second base.

Happ took an elevated fastball for a ball and then fouled off a curveball at the bottom of the zone. He then took a changeup low-and-away for another ball before fouling off a fastball middle-in. Ross spun a slider low and inside and Happ spit on it to run the count full. For the eighth pitch, the Nationals’ righty fired a two-seamer that tailed away.

The pitch veered off the plate -- as both replays and the Statcast strike-zone plot will show -- but Carapazza called the pitch a strike. Instead of a bases-loaded walk that would have cut Washington's lead to three runs and turned the lineup over to the top of the order, Chicago had its push halted with three runners stranded.

Before Happ was ejected, Maddon was also debating whether to leave him in the game at second base as part of a double-switch.

"It's unfortunate for the team," Happ said. "It would've really kept the momentum going there, scored another run. And it's really unfortunate that you have that type of at-bat, eight pitches, make a bunch of good decisions, and not only are you not rewarded for it, you're hurt, you're punished."

Happ was asked if he should have tried to at least foul the pitch off in that situation.

"I made a good decision. You're not going to try to foul a ball off," Happ said. "I'm trained that way. I'm trained to take balls. … I don't get very animated unless it's something that I really disagree with."

Maddon credited the Nationals' lineup -- one that has scored 78 runs in eight games -- for the way it moved the ball around the field and created runs via speed on the bases. That is precisely what the Cubs’ skipper wants to see more often from his own lineup.

Chicago may have been on the cusp of doing just that before Happ was rung up.

"Man, to have a ball called off the plate like that," Kemp said. "That's really tough. That's definitely a big momentum swing in the game right there. Yeah, that one definitely hurt."