Real Madrid needed a late winner from Marco Asensio and VAR's debut in the Champions League to beat a spirited Ajax 2-1 in the first leg of the last 16 on Wednesday.

Ajax have not beaten Madrid in 24 years and thought they were on their way at the Johan Cruyff Arena when Nicolas Tagliafico headed home after a Thibaut Courtois error.

But referee Damir Skomina judged Dusan Tadic to be offside upon review and Madrid showed no pity on their youthful opponents, Karim Benzema and Asensio scoring two precious away goals in the second half.

Hakim Ziyech's equaliser at least keeps Ajax in touch heading into the second leg at the Santiago Bernabeu but Asensio's 87th-minute winner was a sucker-punch in a match the Dutch team had largely dominated.

Their ruled out opener will only add to the sense of what might have been and it was no surprise to see a cluster of red and white shirts surrounding the officials at the final whistle.

VAR has been introduced to the Champions League for the first time in this year's knock-out stages and leaflets were distributed to the media before kick-off, one of the points explaining how reviews should only be for "clear and obvious mistakes".

Still, there was more than an hour to play and Ajax were twice too easily undone on the counter-attack. Frenkie de Jong, who will join Barcelona in the summer, and Matthijs de Ligt, who could follow him, were each dealt a lesson in the ruthlessness of top European football.

Gareth Bale was reinstated to the Madrid starting line-up but there was no place for Marcelo, who missed his first Champions League knock-out game in four years.