Cole Palmer's perfect penalty record came to an end on Sunday when his spot kick was saved by goalkeeper Mads Hermansen during Chelsea's Premier League clash with Leicester City.
The 22-year-old, who Chelsea head coach Enzo Maresca later said was unwell, saw his low effort well-saved by Hermansen who fell to his left to keep out Palmer's strike after Jadon Sancho was fouled in the box.
Chelsea eventually took all three points thanks to Marc Cucurella's daisy-cutter that arrowed into the bottom corner in the 60th minute.
Palmer had the best penalty record in Premier League history before his effort was denied at Stamford Bridge. His 12-out-of-12 penalty record meant he sat above Premier League legends Yaya Touré (11 out of 11) and Dimitar Berbatov (nine out of nine) in the all-time list.
"Cole, yesterday didn't train," Maresca told a post-match news conference. "During the night [he] didn't feel well. And the reason why he didn't train yesterday is because he didn't feel well. So, this morning he woke up and he asked me: 'I want to be on the pitch to help this team, this club to play [in the] Champions League.'
"So in the last two days, he was completely out [with] fever and I don't know if it's something I can say in English ... Diarrhoea. So in the last 48 hours, he didn't train and he was very bad with the fever and this kind of bad feeling.
"But this morning he asked to play the game and this shows how these players want to bring this club where this belongs."
The England international has struggled for form of late. He has failed to score in his last eight games in all competitions and missed a host of presentable chances in the process.
He netted 27 goals and bagged 15 assists in a breakout campaign last season.
Speaking ahead of Chelsea's game against Leicester, Maresca said Palmer is not concerned by his lack of goals.
"When you score a goal you are more happy because your goals help the team to win. But overall Cole is fine. He's happy," Maresca told a news conference on Friday.
"He knows he's struggled to score goals in this moment but that it's something normal that during the season can happen. Watching him during the training session you don't think it's affecting him, he's fantastic."
Before the weekend, Palmer was one of two players with a 100% penalty conversion rate in the last five Premier League seasons -- Callum Wilson being the other.
Information from ESPN's Global Sports Research contributed to this report