Esben Reinholt scored on a driving lay-up with six seconds remaining to lift Denmark to a 79-77 victory over Belarus.
The Danes, playing in their first game of the event being held in Sofia, Bulgaria, had to dig deep to hand Belarus their second straight defeat.
Denmark trailed 73-65 with 2:59 to go after a jump shot by Aliaksandr Semianiuk.
|Mateusz Ponitka was once again the leader of the Polish team|
Anders Haas started the comeback for the Scandinavians, scoring with a drive of his own and then sinking two free-throws.
Soeren Olsen made three of four free-throws to close the gap to 73-72 with 1:44 to go.
Belarus went back in front by five, only for Haas and Olsen to nail jumpers and again reduce the arrears to 77-76. After Sami Eleraky split a pair of free-throws to pull Denmark level, Reinholt scored his go-ahead basket.
Denmark then called a timeout to set up the defense. Belarus got the ball to Anton Papruha but his jumper inside the arc was off target and the Danes celebrated a narrow triumph.
Philip Hertz finished with a team-high 18 points for Denmark and Vitali Liutych led all scorers with 19 in defeat.
Belarus had lost their first game on Thursday to Croatia, 77-73.
Also in Group C, Great Britain clinched their second straight victory at the U20 European Championship Division B on Friday after getting a mean one-two punch from Devon Van Oostrum and Ali Fraser.
Van Oostrum, a member of the senior team at last year's EuroBasket in Lithuania, lit up the Universiada Hall in Sofia with 27 points and Fraser poured in 17 in a 90-78 Group C victory.
There were also victories for Denmark, the Netherlands and Poland on Day 2.
Croatia, who were relegated from Division A last year, led the Brits 67-64 nearly three minutes into the final quarter.
Louis Sayers, catching a pass from Van Oostrum, drilled a three-ball to pull the Brits level.
John Stewart followed with two straight lay-ups before Connor Washington buried a three-pointer for a 74-67 British lead.
Croatia, who got 20 points from Roko Rogic, got no closer than four points the rest of the way.
Sayers was three of four from long range and Van Oostrum hit five of 11.
There was another thriller in Group B, with the Netherlands needing overtime to win 64-56 over Luxembourg at the Arena Armeec II.
The Dutch had suffered a heavy setback to Poland on the opening day but they outscored Luxembourg 9-1 in the extra period.
Sam De Haas had eight of the team's points in overtime.
Kasper Averink finished with nine points, 10 rebounds, five assists and two steals for the Dutch.
The other Group B clash saw a powerhouse Poland win 71-59 over Belgium.
Mateusz Ponitka, one day after pouring in 14 points in a big triumph over the Dutch, was sensational with 18 points and 16 rebounds for Poland.
One of the standouts in the Belgium side is Obasohan Ojomoh.
The 1.83m guard finished with 21 points.
There will be eight games in U20 European Championship Division B on Saturday.