England's bid to win their Euro 2020 group has been thrown into chaos ahead of Tuesday's clash with the Czech Republic after Mason Mount and Ben Chilwell were forced to isolate following Scotland midfielder Billy Gilmour's positive coronavirus test.
Mount and Chilwell embraced their Chelsea team-mate Gilmour on the Wembley pitch after England's 0-0 draw with Scotland on Friday.
Although they have since tested negative, the England duo's close contact with Gilmour forced them into self-isolation on Monday after the news broke that Gilmour has Covid-19.
In a hammer blow to Scotland, Gilmour must quarantine for 10 days and has been ruled out of their decisive game against Croatia in Glasgow on Tuesday.
England manager Gareth Southgate was waiting anxiously to discover if Mount, who has started both of the team's group matches and Chilwell, yet to play in the tournament, will be available to face the Czechs at Wembley.
Asked if the pair could play on Tuesday, Southgate said: "We don't know at the moment. There's obviously got to be quite a doubt.
"There's still a lot of discussions and investigations going on behind the scenes. So at the moment they're isolating and we just have to find out over the next 12 hours or so."
England are assured of a last-16 berth, but Mount and Chilwell could also be ruled out of that tie, depending on advice from health authorities.
Southgate acknowledged the Covid issue was the worst possible preparation to play a Czech team also certain to advance to the last 16.
England are behind the group-leading Czechs on goal difference and must win to ensure they finish in first place.
Southgate's side, who beat Croatia 1-0 in their opener, have been underwhelming so far and were booed off following the drab stalemate against Scotland.
"I can't say it isn't disruptive. We don't really know at this point whether they might be OK for Tuesday, or they could be out for 10 days," Southgate said.
The remaining members of the Scotland squad have passed lateral flow tests, following their negative PCR tests from Sunday.
But the loss of the 20-year-old Gilmour is devastating following his man-of-the-match display against England in his first Scotland start.
Scotland, playing in their first major tournament since 1998, will make the knockout stage of an international competition for the first time if they beat Croatia.
"Billy would have started the game and now he won't, so it's a chance for someone else to come into the team and make themselves a national hero," Scotland boss Steve Clarke said.
In Monday's action, Denmark booked a last-16 clash with Wales after clinching second place in Group B with a 4-1 rout of Russia in Copenhagen.
It has been an emotional rollercoaster for Denmark, who lost their first two matches after the shock of Christian Eriksen's cardiac arrest in the opener against Finland.
With Eriksen on the road to recovery, Denmark finished above Finland on goal difference.
Mikkel Damsgaard and Yussuf Poulsen put Denmark two up before Russia's Artem Dzyuba converted a penalty.
Andreas Christensen and Joakim Maehle wrapped up a cathartic victory at the jubilant Parken Stadium.
"It's insane that we're through. It's fantastic to be part of this, Totally amazing to hear people get crazy," Damsgaard told Danish broadcaster DR.
Group winners Belgium advanced with a 100 percent record after an own goal from goalkeeper Lukas Hradecky and Romelu Lukaku's strike earned a 2-0 win against Finland, who are likely to be eliminated after finishing third with three points.
In Group C, Austria won 1-0 against Ukraine to beat their opponents to a spot in the last 16.
Christoph Baumgartner's 21st-minute goal proved enough for Austria to secure second place behind the Netherlands, who saw off North Macedonia 3-0 in a dead rubber in Amsterdam.
Austria will face Group A winners Italy at Wembley on Saturday for a quarter-final berth.
"We wanted to write history. I'm very proud of my team," Austria coach Franco Foda told uefa.com.
Ukraine face an anxious wait to see if their three points are enough to get them through as one of the four best third-placed teams.
The other game in the group saw Dutch captain Georginio Wijnaldum score twice as the Netherlands made it three successive victories.
Barcelona-bound Memphis Depay had opened the scoring for Frank de Boer's men, who face a third-placed team in Budapest on Sunday.