Dundee United may have been ravaged by illness but it was Dunfermline who were left feeling below par at East End Park on Saturday.
In the build-up to the much-anticipated Championship clash between the league leaders and pre-season promotion favourites, a sickness bug swept through the United camp.
Stewart Murdoch, who would have started, was struck down by the virus and that meant midfielder Willo Flood was drafted in as an emergency right-back.
Also, central defender Mark Durnan and Jamie Robson, who had a great game up against Kallum Higginbotham, both played despite feeling under the weather.
United boss Ray McKinnon confirmed: “We had a sickness bug coming into the game.
“Stewart was really ill and was vomiting pre-match.
“Also, a few players had it during the week as well.
“Just last night (Friday), Jamie and Mark came down with it, too, but they played when feeling poorly.
“We had Willo stepping in at full-back and we were a bit disjointed at the back.
“But all credit to the lads because they produced a great performance.
“I think we have seen an improvement in the players and the shape of the team.
“The boys were excellent.
“I think it was (the best display of the season) and perhaps we could have scored a few more goals.
“We limited them to very little and went quite direct.
“I thought we were very dangerous when we won the ball back.
“So there were lots and lots of positives.”
One of which was the class act that was Fraser Fyvie.
He more than anyone helped United stamp their authority back on the Championship with this remarkable win.
Going into the game, the Pars were sitting pretty at the top of the table and were scoring goals for fun.
However, the Tangerines tore them apart and fired a stark warning to the rest of the division that they are back in business after a dip in form.
Fyvie was at the heart of all that was good about the Tangerines.
Just when you thought the Pars were gaining traction in the game, United went up the park and scored on 35 minutes.
Robson, looking anything but ill, raced up the left and his cross-shot was pushed away by Dunfermline goalie Sean Murdoch.
Unfortunately for the Fifers, the parry landed right in front of Fyvie, whose drilled, low shot from 10 yards found the back of the net.
The advantage was doubled two minutes before half-time when Scott McDonald blasted home from close range.
The Pars conceded a freekick inside their own half when Lee Ashcroft brought down McDonald. Keatings sent the setpiece into the box and it struck the body of United defender William Edjenguele and fell for the wee Australian poacher, who slammed the ball past Murdoch.
Remarkably, it could have been three before half-time as the visitors broke three-on-two.
Paul McMullan was the one who was played in but his shot was deflected up into the air. Billy King saw his chance and sent a shot crashing off the Pars bar before it was finally cleared.
The stage was then set for Fyvie to bring the house down with a brilliant strike just before the hour.
A Keatings freekick hit the Dunfermline wall and eventually the ball made its way out right to Flood, who drilled a cross back over. The ball ricocheted again and spun up for Fyvie, who was standing just outside the box and smacked it on the half-volley high into the net past Murdoch.
The home team got a goal back on 77 minutes when half-time substitute Callum Smith headed home after a deflection but that was all Dunfermline could manage on a day that left them feeling queasy.
Pars skipper Callum Morris felt they just never got going against his former club.
He said: “We are all disappointed.
“I don’t think there was a lot in the game but I think we all know we haven’t played as well as we can.
“We had been doing well all season, which has got us to where we are, but we didn’t do that against United.
“We’ve not gone behind too often this season and perhaps a couple of heads went down.
“Maybe we need to be more resilient.
“The overriding feeling is one of disappointment because we know we didn’t play as well as we can.
“There was a great turnout from the fans and it’s just disappointing we put on a performance like that for them.
“But we will look at the video of the game and we will bounce back again.”
As for his manager Allan Johnston, he felt the half-time scoreline – 2-0 to the Tangerines – was extremely harsh on his players.
“There was nothing in the game in the first half,” he said.
“I thought we were maybe slightly the better team.
“I thought for us to be 2-0 down at half-time was very flattering for Dundee United.
“To be fair, I thought they were the better team in the second half and we have to learn from that.
“When you lose a goal you have to handle it better, still work hard, do the right things and keep your shape.
“We were maybe a bit naïve and were caught on the counter-attack a couple of times.
“We didn’t play anywhere near the level we have been playing at but there is a long way to go.”