Randy Edsall’s team dropped to 4-4, 2-2 ACC with its loss to Boston College. (Nick Wass/AP)

The Maryland football team has received an undeniable boost this season from its defense, a remarkable turnaround for a unit that ranked among the nation’s worst in 2011. The veteran-laden front seven has terrorized opposing quarterbacks with disguised blitzes, pressuring and sacking their way into the upper echelon of the nation’s statistical rankings and slowing opposing offenses in a manner unseen through Coach Randy Edsall’s inaugural season in College Park.

And yet problems linger.

“Two weeks in a row we could have won the game for our team, and we let our team down,” defensive lineman A.J. Francis said Saturday following Maryland’s 20-17 loss to ACC cellar-dweller Boston College. “We have to play better on defense. On the last drive, we didn’t.”

This most recent defeat did not have the heart-pounding anguish of last weekend’s two-point home loss to North Carolina State, but for the second straight game Maryland ceded a late, game-winning drive. This time it was Eagles junior Chase Rettig, surrounded by max protection that kept the Terrapins’ pass-rushers at bay, marching Boston College 85 yards on 13 plays, capped off by a 14-yard touchdown pass to Jonathan Coleman, who found himself wide open after blown coverage, with 52 seconds remaining.

Instead of moving within one game of bowl eligibility, Maryland (4-4, 2-2 ACC) sank to .500 with a brutal November slate ahead.

“It’s tough to see another lead slip away, but it’s just like acupuncture,” said Terrapins running back Wes Brown, who rushed for a team-high 73 yards. “Just hitting the wrong points. We just have to keep working to get back on track and hit the right keys.”

After Coleman’s touchdown, the Terrapins took over in an eerily similar situation to the one they faced in last weekend’s loss to North Carolina State. Freshman quarterback Caleb Rowe, who engineered a frantic drive in the waning moments against the Wolfpack, took the field at the Terrapins 31-yard line Saturday. But his final pass of the day zipped across the middle and went straight into the arms of Boston College safety Spenser Rositano, Rowe’s third interception of the day.

“I feel for the kids. I really do,” Edsall said. “I want them to win so bad, because they’re doing all the things we’re asking them to do and playing their hearts out. We’ve got to get them to play a little smarter, and when they get in these situations, to believe in themselves a little more. That’s what’s so frustrating and disheartening for me. We’re just not getting those wins for these kids.”

Maryland had every reason to collapse after the wrenching loss to N.C. State, in which Craddock’s 33-yard field goal attempt banged off the left upright with two seconds left. In the days that followed, the Terrapins would learn that they had lost their starting quarterback, backup quarterback and second-leading wide receiver to season-ending injuries suffered in that game.

But for some time Saturday, it appeared that a sluggish first half would give way to another late Maryland rally.

Midway through the fourth quarter, freshman wide receiver Stefon Diggs, Rowe’s roommate during summer school, seemed poised to bring the Terrapins back from the brink. His previous highlight-reel runs this season typically featured some sort of juke, spin or disappearing act, but after catching a Rowe pass near midfield, he simply outran the Eagles, sprinting from the Boston College logo at midfield down the sideline for a 66-yard touchdown that put Maryland up 17-13 with 8 minutes 47 seconds left. Diggs finished with 11 receptions for 152 yards, both career highs.

With quarterbacks Perry Hills and Devin Burns out for the year, Maryland found itself with limited offensive options. Marcus Leak, Maryland’s second-leading receiver, also broke his toe against N.C. State, and the Terrapins were forced to abandon their read-option attack against Boston College (2-6, 1-4) with Rowe under center for his first collegiate start.

“It’s fun having the ball in your hands to win the game,” Rowe said. “Unfortunately today wasn’t the day. I’m definitely ready to get better. As a football player, you can’t ever stop getting better. I’m ready to learn from these mistakes and continue with the season.”

Rowe completed 23 of 42 passes, both single-game highs for the Terps this season, for 240 yards.

With 6:26 remaining in the third quarter, Nigel King, Leak’s replacement in the starting lineup, caught a wide-open one-yard touchdown pass on a fade route when three Eagles defenders bit on an inside route by Diggs. A 28-yard field goal by Brandon Magistro, who replaced the beleaguered Craddock after the Aussie import missed a 33-yard attempt in the first half, brought the Terrapins within 13-10 late in the third quarter, all but erasing a 13-0 halftime deficit.

Meanwhile, Maryland’s defense began relentlessly blitzing Rettig, flushing the Boston College junior out of the pocket or sacking him altogether. Joe Vellano, quietly putting together another all-ACC year along the Terrapins’ defensive line, stripped Rettig on the Boston College drive that followed Diggs’s touchdown, and Francis pounced on the fumble.

But a Maryland three-and-out gave the Eagles possession again, setting up Rettig’s heroics as he found enough space to complete six passes of at least 11 yards while eating up the clock. Boston College converted on twice on third down that drive; before that, it was just 1 for 11 on third-down conversions.

“We got a lot of pressure on him early, but we couldn’t get the pressure on him when we needed to win the game, and that’s why we lost,” Francis said. “We were in his face while he was throwing, but we weren’t hitting him. Personally, I feel like we did a good job all the way until the last drive.”