Both teams concidentally had their best World Cup showings 20 years ago. Croatia relied on little more than improvisation in that segment - and in some others, too - for far too long, and Denmark only exposed it.
Both sides in the tunnel, kick off less than 10 minutes away.
But captained by former Spurs standout and current Real Madrid star Luka Modric, Croatia made it through their three group stage games with a flawless 3-0 record and emerged as the fourth-highest scoring side in the 2018 World Cup tournament, according to FIFA.com, and soccer experts believe the current Croatian team may be better than the 1998 edition that made it to the semifinals of the World Cup that year, ultimately to finish third.
Luka Modric and Ivan Perisic are set to be the only players retaining their place from the Group D win.
Croatia were awarded an injury time spot kick after Denmark's Mathias Jorgensen brought down Ante Rebic with this challenge in the penalty area. He was played clean through by Modric.
Rebic, along with Andrej Kramaric and Ivan Perisic may feature ahead of the midfield duo of Modric and Rakitic. Perisic's pace and end product can prove to be the difference between the two sides.
39' - A set piece for Croatia nearly results in a goal. Coming to Russia, Croatia won one and lost one practice game before the main tournament got underway. He broke his ribs against Peru and has been out ever since.
Striker Yussuf Poulsen returned for Denmark after suspension.
Christian Eriksen - The playmaker is Denmark's biggest hope of defeating Croatia.
Follow live updates as Croatia take on Denmark in the last 16 of the FIFA World Cup.
But it was Schmeichel, the son of former Denmark goalkeeper Peter Schmeichel, that sent it to extra time with his penalty save on Modric's attempt.
Pione Sisto: The nimble-footed, wily left winger can possess a lot of questions to Croatia's defence. Croatia 2-2 Denmark after nine penalties.
In the United Kingdom, a live stream of the Croatia vs. Denmark 2018 FIFA World Cup Round of 16 game will be carried by the ITV and may be accessed, inside the United Kingdom only, using ITV Hub. Scoring has been an issue for them, Denmark have scored just two goals in three games at the World Cup.
The Croat captain said: "I don't like to compare players, to compare others to myself". He has scored two goals in Croatia's charge to the last 16 with three wins out of three.
Croatia was arguably the best team in the World Cup group stage, and it will look to continue its run in the knockout rounds when it faces Denmark in Nizhny Novgorod, Russia on Sunday.
Croatia entered the match after impressing in the group stage, including a 3-0 dismantling of two-time champion Argentina at the same stadium.