LAS VEGAS -- JaJuan Johnson proved Tuesday that he wasn't oblivious to his underwhelming Las Vegas Summer League debut on Monday, in which he posted a mere six points and five rebounds over 22 minutes as the Celtics ousted the Hawks, 87-69.

Johnson sprung back to life as he rebounded -- literally and figuratively -- with a more productive effort in Tuesday's 79-74 win over the Chicago Bulls. Johnson chipped in seven points on 3-of-6 shooting, but more importantly he snagged a Summer League-high 12 boards, while helping to anchor a Boston defensive effort that held the Bulls to just 35.7 percent shooting. Though he was credited with only one block, Johnson played a role in altering several other Chicago shots around the rim over his 31:36 of floor time.

Asked about the differences between the two games, Johnson offered a quick joke before touching on the more important matter at hand.

"Just a later game?" Johnson quipped, wearing an expression that suggested he fully understood that Monday's outing can't be the norm for him. "No, I don't know, it's just how it is some days, but obviously I just need to work on being more consistent, on both ends. There's still things I see I can do better, but obviously I'm heading in the right direction. Getting to play is a plus."

While some are expecting Johnson to come through with one of the more accomplished game logs over the course of this summer slate, he still has hurdles he's steadily trying to work over. With game minutes and practice time so limited last season due to the NBA lockout and the Celtics' injury woes, Johnson hasn't had the chance to play routinely at a high level for some time. Also, he finds himself on a Celtics Summer League roster loaded with offensive firepower, which lessens the chances of him establishing himself as a go-to scorer. Instead he's had to become a steady part of a well-oiled machine on that end of the floor, while finding other ways to positively impact the game, such as by cleaning up on the glass. On Tuesday, Johnson looked like a player fully aware of this situation.

"I thought [Johnson] was great," C's Summer League coach Tyronn Lue said Tuesday. "They were fronting him on the post and they were fronting Jared [Sullinger] also, so we've got to do some different things to get those guys open on the post, but I thought defensively [Johnson] was great. His shows were great, his help-side defense was great. I thought he had more than one block. They only gave him one, but he had 12 rebounds tonight. He was just real active and it was a good night for JJ."

Consistency becomes the next, and perhaps more important, ingredient for Johnson -- a fact he appears to be embracing now.

"Obviously minutes are going to be tough to come by this upcoming season, so I've definitely just got to work on being consistent with everything," Johnson said. "It's going to be pretty competitive, so I've just got to be ready."

The addition of Sullinger through the 2012 NBA Draft will only further that competition, as it's likely that both he and Johnson will be fighting for minutes in the rotation next season. The two have known each other for a while, even though their collegiate careers overlapped only one season (Johnson was a senior at Purdue when Sullinger was a freshman at Ohio State). Johnson said they both were aware of what the other was doing on the court during that year, and while one would think Sullinger would prove to be the latest obstacle in Johnson's quest for minutes, the second-year forward downplayed that idea, stressing the duo's ability to co-exist on the floor.

"Obviously I think we both can play on the floor at the same time, kind of like we've been doing," Johnson said. "I think he's capable enough to guard the four and the five. I can guard the four, three, so it's a possibility that we could be on the floor at the same time, and I'm excited to play with him."

Sullinger and Johnson have emerged as Lue's preferred starting frontcourt (along with Kris Joseph), and on Tuesday they co-existed perhaps better than ever before, particularly on the glass. Sullinger finished with a game-high 14 rebounds, but Johnson's dozen weren't far off. Of the 26 boards taken down between the two, eight came on the offensive end -- an area in which the Celtics would love to see improvement this coming season.

"It's just a conscious effort," Johnson said of Tuesday's rebounding effort. "Obviously if your shot's not falling, you've got to do something to contribute to the team, if that's defense, on the glass, just something. Myself and Jared, I think we did a pretty good job hitting the glass [Tuesday], so that's good.

"We know pretty much we're the ones who are supposed to be crashing every time. On the offensive end the guards get back, so we do know that and we do kind of talk to each other a little bit."

While Johnson and Sullinger's relationship in college was primarily business, it will most likely become more personal now, and Johnson acknowledged that the two have already spent time working out together prior to Summer League.

"We did before we left to come here, and that was pretty good, just playing against each other and with each other, I guess, at the same time," said Johnson. "It's been pretty cool."

Johnson acknowledged that Sullinger's presence will help the competitive atmosphere in practices next season, along with the seasoned veterans already on the roster. That competitiveness will continually reinforce the importance of consistency for Johnson.

"In practice, even with last year, it's not just [Sullinger now]," Johnson said. "We've got Brandon [Bass], [Kevin] Garnett, [Chris] Wilcox, all those other guys, so it's going to do nothing but help the intensity of practice and help our team get better as a whole."