But Tielemans’ second-minute strike in Cologne eased fears of yet another major tournament flop from star-studded Belgium.
Kevin De Bruyne wrapped up the points in the closing stages to leave all four teams in the group level on three points.
The stage is set for a dramatic final round of fixtures in the battle to reach the last 16.
Belgium face Ukraine and Romania play Slovakia on June 26.
With 45 rungs separating the two nations in FIFA’s rankings, third-placed Belgium’s 1-0 loss to Slovakia on Monday was the biggest upset in European Championship history.
Romania, ranked in 47th place, competed gamely as they chased their own shock, but this time Belgium’s superior class proved decisive.
Having bowed out at the group stage of the 2022 World Cup and lost in the quarter-finals of the last two Euros, Belgium’s golden generation have given themselves fresh hope of finally delivering on their vast potential.
Romania had powered to a 3-0 win against Ukraine on Monday — their first victory in a major tournament since beating England at Euro 2000.
Despite this loss, Edward Iordanescu’s team are still in contention to make the Euro knockout stage for the first time in 24 years.
Belgium had failed to score in over 300 minutes at major tournaments since netting against Canada at the last World Cup.
They needed less than two minutes to end that drought.
– Influential De Bruyne –
A sweeping move climaxed when Jeremy Doku’s pass found Romelu Lukaku in the Romania penalty area and he laid the ball back to Tielemans, who smashed a powerful low strike past Florin Nita from the edge of the area.
Romania’s Tottenham defender Radu Dragusin went close to equalising moments later with a towering header that Koen Casteels tipped over at full stretch.
After an injury-plagued season with Manchester City, in which he failed to reach his usual sky-high standards, De Bruyne had looked below his best against Slovakia.
The Belgium captain was far more influential this time, with a lung-bursting surge that ended with a pass to Dodi Lukebakio, whose strike was pushed away by Nita.
Doku was denied by another good stop from Nita after wriggling through the over-worked Romania defence.
Valentin Mihaila wasted a golden opportunity to equalise soon after half-time, pouncing on Amadou Onana’s wayward pass and sprinting clear, only to blaze high into the stands.
De Bruyne was moving through the gears ominously, curling just past the far post from 20 yards, then drawing a smart save from Nita with a shot on the turn.
Lukaku had two goals, including a late equaliser, disallowed by VAR against Slovakia.
The striker was denied by VAR again in the 63rd minute when he converted De Bruyne’s pass before being ruled narrowly offside.
Romania nearly profitted from that escape as Dennis Man raced clear, but couldn’t find the accuracy to beat Casteels.
De Bruyne finally delivered the knockout blow in the 80th minute, running onto Casteels’ long punt and firing past Nita.
AFP