Virginia’s Braxton Key, left, De’Andre Hunter, center, and Kyle Guy look on late in the second half of Friday’s loss to Florida State in the ACC tournament semifinals. (John McDonnell/The Washington Post)

Virginia center Jay Huff had a clear path to the basket late in the second half against Florida State on Friday when forward Mfiondu Kabengele, seemingly out of nowhere, swooped in to block the 7-footer’s layup attempt into the hands of Florida State teammate Trent Forrest.

The show of athleticism on the part of the Seminoles encapsulated a trying night for top-seeded Virginia, which lost in the ACC tournament semifinals, 69-59, to an opponent it had beaten by 13 points to open conference play three months ago.

This time, the Cavaliers (29-3) were virtually powerless to stop No. 4 seed Florida State (27-6), which used its considerable length at every position to end Virginia’s nine-game winning streak and deny the ACC regular season champions a shot at a second straight conference tournament title.

“They’re a very athletic team, very long, and it did disrupt us a little bit,” Virginia guard Kyle Guy said. “It’s very evident what we need to fix, and we’ll be ready come next week.”

By then, Virginia will have learned its opponent and destination in the NCAA tournament, but until the Cavaliers play again, they’ll have ample time to stew over allowing the Seminoles to shoot 56.5 percent. Only Duke shot a higher percentage (57.8) against the country’s top-ranked outfit in terms of defensive efficiency.

During its recent winning streak, Virginia had permitted only one opponent to shoot higher than 40 percent.

“They were just the tougher team tonight,” Cavaliers point guard Ty Jerome said. “More physical, all of it.”

The Seminoles will play the winner of Friday’s late Duke-North Carolina semifinal.

Jerome’s personal misfortunes continued in the same building, Spectrum Center, where Virginia last season became the first No. 1 seed in NCAA tournament history to lose to a No. 16 seed following a stunning upset by Maryland-Baltimore County, 74-54.

The junior shot 4 of 13 against Florida State, including 2 of 9 from beyond the arc, one game after going 1 for 11 in Thursday’s 76-56 win against North Carolina State in the quarterfinals.

In three games at Spectrum Center, Jerome has shot 11 for 40 and just 4 for 24 from three-point range.

“I don’t know. Sometimes the ball doesn’t go in,” Jerome said. “Just go back, get back to Charlottesville, get back in the gym and get ready for our next game.”

Among the Cavaliers “Big Three” of Guy, Jerome and De’Andre Hunter, only Hunter (team-high 13 points) shot at least 50 percent against the Seminoles, whose size advantage and leaping ability throughout their deep roster helped produce a 35-20 margin in rebounding.

Late in the game, Florida State twice collected offensive rebounds, taking valuable time off the clock and preventing the Cavaliers from perhaps staging a rally.

Even when the Cavaliers did gain possession, Florida State forced nearly desperation heaves with the shot clock winding down, with Jerome and Huff both missing badly on three-point attempts.

“You get into this part of the year, the postseason, and the defense cranks up,” Virginia Coach Tony Bennett said. “The physicality increases, and probably the game even slows down some, and so you’ve got to knock down shots when you get them. We played a team that was very good defensively.”

Virginia led only briefly in the second half, its last advantage at 45-44 with 13:28 to play. But the Seminoles responded by reeling off a 16-5 run, leading to a timeout from Bennett.

The closest the Cavaliers came in the final minutes was within 65-59, but Kabengele made both ends of a one-and-one, and Terance Mann punctuated the triumph with a two-handed dunk, giving Florida State a crack at its first ACC tournament championship since 2012.

“We grow from this experience,” Bennett said. “We had some chances to win the game. I think we went up one, but Florida State played well. They defended well. They were sound, and tonight they were the tougher team, or more physical. They’re physical that way.”

Seminoles reserve guard David Nichols in particular was able to exploit his matchup against diminutive Virginia guard Kihei Clark, a freshman. Nichols repeatedly backed down Clark on the low block to sink short jumpers.

Nichols ended with a game-high 14 points, making 6 of 8 shots. The senior entered the game shooting 38.5 percent and scored just five points in the first meeting between the teams on Jan. 5 at John Paul Jones Arena.

During an 11-1 Seminoles run in the second half, Nichols made three consecutive field goals, once even scoring on Hunter, the ACC defensive player of the year and projected NBA lottery pick who has drawn comparisons to Toronto Raptors forward Kawhi Leonard, among the best two-way players in the world.

“It was obvious that our kids were really locked in for this game, and a lot of it is because we have such a tremendous amount of respect for the job that Tony does and the legacy he’s built at Virginia,” Seminoles Coach Leonard Hamilton said of the ACC coach of the year. “It was difficult. We played a lot of guys.”