Cleveland scored Game One's first six points and jumped to an 11-point lead early, with Evan Mobley scoring eight of his 16 points on the day less than six minutes in. The Cavaliers never looked back after their initial start, pushing their advantage to as many as 20 points.
"Our initial start was a big portion," Magic coach Jamahl Mosley said of the Cavaliers' ability to pull ahead. "Our group was poised and we were able to fight back. But when you go 19-of-30 from the free-throw line, 8-of-(37) from (3-point range), it's hard to make up ground in those areas."
After falling behind by 14 points coming out of halftime, however, Orlando stormed back to pull within four points. Paolo Banchero, who scored a team-high 24 points, hit a three-pointer to cap a 12-2 run.
Banchero's scoring output matched Shaquille O'Neal for the most by an Orlando player in his first playoff game. Banchero also had seven rebounds and five assists on Saturday.
Jalen Suggs scored six of his 13 points during the surge.
Cleveland regained control going into the fourth quarter when Caris LeVert closed the third period finishing on layups while being fouled. He converted one of the two and-one opportunities, accounting for all five of his points for the game coming off the bench.
The Cavaliers kept the run going into the fourth quarter before Orlando battled back to within a single-digit margin. Cleveland answered each Magic comeback push, however, thanks to an outstanding defensive effort.
Game Two is Monday night in Cleveland.
The Cavaliers held the Magic to just 32.6% shooting from the floor at 28 of 86, including 8 of 37 from three-point range.
Allen credited the defensive intensity in large part to the reserves.
"We wanted to bring the physicality from the beginning," Allen told Bally Sports Cleveland. "Guys like Georges (Niang), guys like Isaac (Okoro), they threw the first punch."
Niang and Okoro each made a steal - part of the nine the Cavaliers swiped altogether - and Okoro blocked a shot. Mobley's double-double performance, which included 11 rebounds, also produced three blocked shots to match Orlando's Franz Wagner and Jonathan Isaac for the game-high.
Isaac and Wagner each scored in double-figures for the Magic with 10 and 18 points, and their play on defense helped give Orlando hope for a rally. Isaac made three steals to go with his three rejections, while Gary Harris added another three steals and Suggs swiped two.
The Magic's play on defense forced Cleveland into a lengthy three-point shooting drought. After making their first five, the Cavaliers missed 15 straight 3-point attempts from the late first quarter through the third.
Darius Garland snapped the cold spell to open the fourth quarter, however, part of his 14 points. Garland also dished eight assists.
Another timely three-pointer came from Mitchell with 4:44 remaining, part of his game-high in scoring, to stymie an Orlando rally attempt and effectively put the game away.
Mitchell shot 3 of 8 from deep and 11 of 21 from the floor overall. Mobley shot 2-of-4 from 3-point range, 6-of-12 from the floor overall, and grabbed 11 rebounds. Max Strus added another nine rebounds to go with seven points.
