“We’re not the deepest. We can’t afford to have many breakdowns,” Virginia Coach Tony Bennett said. (Gerry Broome/Associated Press)

Virginia forward Akil Mitchell feared the worst the moment he fell to the floor midway through the second half Tuesday against Clemson. Mitchell had injured his right foot three nights earlier in a game at North Carolina State, and the pain he felt in the same foot Tuesday was equally biting. He slapped his hand against the court three times.

“I thought I was done,” Mitchell said Thursday. Much to the relief of Virginia’s coaching staff and fans, he wasn’t.

From the first day Mitchell arrived on campus, Coach Tony Bennett has stressed that the Cavaliers perpetually walk “a fine line” between success and disintegration, in large part because of their style of play. This season, as the team has gotten off to its best start in decades, limited roster numbers have narrowed No. 16 Virginia’s margin for error even further.

As the Cavaliers (18-3, 5-2 ACC) prepared for Saturday’s matchup against No. 21 Florida State (15-6, 6-1) in Tallahassee — a city in which Virginia has not won since 2001 — another injury could have meant the evaporation of that margin for error.

“We’re already down to what, seven players?” Mitchell said. “I got scared, and I had a whole lot of other people tell me they were scared, too.”

Mitchell was close in his estimation. Following the December departures of guard KT Harrell and forward James Johnson, as well as the right ankle fracture suffered by center Assane Sene two weeks ago, Virginia is down to eight available scholarship players. That’s not an ideal situation for any team, much less one centered on a defensive approach that, for better or worse, keeps nearly every game closely contested.

The Cavaliers are executing Bennett’s pack-line defense effectively this season; Virginia possesses one of the stingiest defenses in the country. But its strength lies in its ability to slow down the game, limit possessions and frustrate opponents into taking contested shots.

That works out fine when the Cavaliers’ offense operates efficiently, which was the case Tuesday during Virginia’s 65-61 win over Clemson. But consistent offensive production has evaded the Cavaliers this season, which often has added to the pressure to perform precisely on defense.

Four of Virginia’s past six wins have been by five points or fewer; all three of the Cavaliers’ losses this season have been by three points or fewer.

“You have to be alert, and you have to be perfect at all aspects of the game — on defense and on the offensive end — and you have to execute,” junior guard Jontel Evans said. “It has you thinking out there. You can’t be out there with your mind wandering. You have to be focused in order to do what we do.”

Or, as Bennett said following the Clemson win: “We need everything. We’re not the deepest. We can’t afford to have many breakdowns. We have to play at a very high level on the defensive end to be in games and then to win games.”

That again will be the case Saturday at Florida State. In past seasons, the Seminoles have thrived and fallen with their defense, as well. But this year, Leonard Hamilton’s squad has demonstrated more balance. Florida State leads the ACC in field goal percentage defense (37 percent) and steals (8.9 per game) and ranks second in blocks (6.1 per game), but that’s nothing new.

Led by guard Michael Snaer, the Seminoles also rank in the top three in the conference in points per game (73.6), field goal percentage (46.4) and three-point field goal percentage (42) in ACC play.

Florida State also possesses a physically imposing stable of post players, and Virginia’s coaches emphasized during practice Thursday that everyone — especially the team’s guards — would have to rebound aggressively Saturday in order for the Cavaliers to have a chance to succeed. Such is life on a fine line.

“Last year, it got to me a lot,” said Mitchell, a sophomore. “You’ve really got to be locked in, especially in practice. . . . You’ve really got to be on your toes every time you step on the court.”