There are no concession speeches planned, no white flags ready to be raised. The four teams involved in the American League East round robin seem intent on sustaining one of the most entertaining divisional melees in years for as long as possible, a notion that gained further credence Tuesday at Fenway Park.

On a night where the Red Sox had an opportunity to inflate their divisional lead to three games, the team instead saw the Orioles rebound from Monday’s 12-2 loss with a 6-3 victory. Based on the evidence of the first 144 contests of the season, there likely will be more such exchanges in the remaining 18 contests to come between the Sox and their American League East rivals.

“It might be the toughest division in baseball, when you consider the strengths of the individual clubs, the ballparks in which we play,’’ said Red Sox manager John Farrell. “There’s no gimmes against anyone in this division at all. And you kind of like the fact that everyone is back in division play, so the schedule kind of evens out to a certain extent.’’

Just as the Red Sox erupted for five early runs Monday, so, too, did the Orioles on Tuesday. They bashed Drew Pomeranz for five runs in the second inning, suggesting a roughly equal exchange of divisional heavyweights. Pomeranz, starting on seven days’ rest as the Red Sox try to manage his workload, saw his command betray him in the fateful second.

A Mark Trumbo single and a Chris Davis walk served as a prelude to a J.J. Hardy three-run homer on a poorly located fastball. After Pomeranz issued a walk to No. 8 hitter Drew Stubbs, he hung a breaking ball to Nolan Reimold, which went screaming just over the Green Monster for a two-run blast that dropped the Sox into a 5-0 hole.

Pomeranz entered the game with a career 2.26 ERA against AL East opponents, including a 2.52 mark in four starts this year. But against the Orioles, he bore little resemblance to the pitcher who’d achieved those marks.

“Maybe a little bit of a surprise,’’ Farrell allowed of his pitcher’s performance. “We certainly expected Drew, particularly with a couple of added days of rest, to maybe be a little more sharp.’’

When Pomeranz (2-5) yielded a leadoff single to open the third, Farrell elected to employ an early hook. Pomeranz’s two-plus-inning start was the second shortest of the year by a Sox starter, surpassed only by an April outing that Joe Kelly left when injured.

In some respects, Pomeranz’s rapid fade resembled his first start with the Red Sox, when he yielded five runs in three innings against the Giants. In that start, as with Tuesday’s, he pitched on extra rest, outside the five-day routine within which he’d been effective for much of the year.

“Sometimes you can be out of rhythm a little bit [with extra rest],’’ said Pomeranz. “[But] it just comes down to me not making pitches the way I need to . . . The ball was just shooting up and out of the zone to the other side of the plate. It was really frustrating how I didn’t make adjustments when I needed to and got in trouble because of it.’’

Yet the Sox seemed capable of surmounting Pomeranz’s struggles in the bottom of the inning.

A one-out double by Travis Shaw, a Chris Young walk, and a single by Jackie Bradley Jr., loaded the bases against Dylan Bundy. Both Ryan Hanigan and Dustin Pedroia negotiated walks to make it a 5-2 game.

But in a frequently repeated theme of the game, the Red Sox lineup couldn’t capitalize on the threat: Xander Bogaerts was punched out on a Bundy changeup and David Ortiz grounded to first.

From that point, the game remained in check. The Sox bullpen plastered six zeros on the scoreboard, with Heath Hembree and Joe Kelly each contributing a pair of shutout innings.

The Sox managed one more run on Bogaerts’s homer in the fifth. The home run was his 19th of the year, the most by a Sox shortstop since Nomar Garciaparra’s 28 in 2003.

But they’d come no closer, failing to capitalize on a number of hittable offerings, with one lineup member after another firing his bat in frustration at the inability to demolish fastballs over the plate.

Bundy (9-5) wobbled but never plummeted from his tightrope. After he walked Young with one out in the sixth, the starter entrusted that two-run advantage to an Orioles bullpen that entered the night having converted 78.9 percent of save opportunities, the top success rate in the American League.

Orioles manager Buck Showalter summoned Tommy Hunter to face Hanigan. Hunter had held righties to a .217 average and .632 OPS entering the night, with lefties hitting .308/.700 against him, thus raising questions about whether Farrell might summon Sandy Leon (.333/.850 vs. righties this year).

The Sox are trying to determine how to allocate second-catcher duties between Hanigan — a respected game-caller who entered the night with a .170 average — and Bryan Holaday. On this night, they stuck with Hanigan. He grounded into an inning-ending double play.

The catcher was far from alone in failing to seize opportunities.

Indeed, when Leon hit for Hanigan against Orioles closer Zach Britton with two on and two out in the eighth, he grounded harmlessly to short, punctuating the Sox’ 1-for-10 performance with runners in scoring position. Ortiz, Mookie Betts, and Hanley Ramirez were a combined 1 for 13.

Jonathan Schoop homered in the top of the ninth, giving the Orioles an insurance run that proved unnecessary. Britton closed out his 42d save in as many chances, the third-longest streak in big league history.

Even with the loss, however, the Red Sox maintained their two-game lead in the division over both the Blue Jays and Orioles, thanks to Toronto’s 6-2 loss to the Rays.

On Wednesday, the Sox will turn to 20-game winner Rick Porcello in hopes of maintaining – or expanding – that margin.

“We’d be lying if we said we don’t look at the [standings] every night and see what the [Jays] did,’’ said Travis Shaw.

“We control our own destiny and want to win obviously, but tonight when you lose and see the Blue Jays lose, you’re kind of in the same spot and looking tomorrow to pick back up.’’

Alex Speier can be reached at alex.speier@globe.com. Follow him on twitter at @alexspeier.