Arizona Diamondbacks pitcher Merrill Kelly didn’t hide his frustration after Monday’s game at Chase Field, and Arizona Sports says the issue centered on what the D-backs believed was sign-stealing from Chicago Cubs third base coach Quintin Berry.

Kelly stepped off the rubber and looked toward Berry during the fifth inning of what ended as a 7-0 Chicago win, according to Arizona Sports. The back-and-forth that followed between the two dugouts made it clear this wasn’t just a routine baseball gripe. It was the kind of moment that can change the feel of a game, even before the final score settles in.

Kelly’s main complaint was about where the sign-stealing was coming from. As Arizona Sports reported, he called it “bush league” and said sign-stealing is part of baseball, but should stay between players. He drew a line between a runner on second base or a hitter picking up something from a pitcher’s glove and a coach relaying information from outside the lines.

He also said Berry appeared to signal his hitters any time Kelly was throwing a changeup, which Kelly described as his most important pitch most of the time, per Arizona Sports. Even so, Kelly said the Cubs didn’t do much with the pitch, noting they had only two hits against the changeup. That didn’t seem to soften his view of the situation, though. He called it the most egregious example he’d seen from coaches and said it should stay between the players.

There was plenty of reaction from the home dugout, too. Arizona Sports quoted D-backs bench coach Jeff Banister saying, “That’s part of the spirit of the game at times, right? I mean, it’s competitive. It’s August.” Manager Torey Lovullo also addressed it, saying nothing personal was barked back and forth and that there was some gamesmanship involved.

It’s the kind of baseball dustup that fans in Phoenix know well: a little strategy, a little irritation, and a lot of emotion packed into one inning. For the Diamondbacks, it was one more reminder that even in a game that ends 7-0, the real heat can come from what happens between the lines.

Full details at Arizona Sports.