London - England were left facing an anxious wait to discover the full extent of an ankle injury suffered by Sam Underhill while the back-row forward was playing for club side Bath on Sunday.
Underhill, one of the stars of England's November international programme, was forced off during Bath's 23-16 win over Leicester in the English Premiership.
Bath coach Todd Blackadder was unable to shed much light on the extent of Underhill's injury, a concerning development for England given their blockbuster opener to the 2019 Six Nations, against reigning champions Ireland in Dublin, is just over a month away
"He (Underhill) was brilliant. He and Francois Louw were all over the ball tonight," said Blackadder.
As for Underhill's injury, the former New Zealand international added: "He's just rolled his ankle. It was serious enough for him to come off."
Victory saw Bath move up into fifth place in the table following a poor start to the season and a delighted Blackadder said: "I was really pleased with our persistence and resilience in playing at the right end of the field, just keeping attacking."
By contrast, defeated Leicester, once the undisputed kings of the English club game, are in ninth place and still very much involved in a battle to avoid relegation.
"It feels really raw at the moment," said Leicester boss Geordan Murphy. "It's tough in this league at the moment. It's a dogfight," the former Ireland international added.
Elsewhere, Bristol moved six points clear of the lone relegation place after a second-half revival saw them beat basement club Newcastle 35-28.
Bristol were 10 points behind at the break but Tom Pincus's try three minutes from time capped an excellent fightback, with Charles Piutau, Luke Morahan, and Harry Randall also scoring tries for the southwest side.
Ian Madigan converted two and kicked two penalties with Callum Sheedy adding a penalty and a conversion.
Newcastle scored tries through Vereniki Goneva, Adam Radwan and Callum Chick, with ex-England playmaker Toby Flood kicking two conversions and three penalties.
Bristol coach Pat Lam said a "simple message" to his side at the interval had produced the desired response.
"In that first half we made error after error, there were 12 turnovers from us, which gave them easy field position so they could hang on the ball for long periods and although our defence was good, eventually the pressure told," Lam explained.
"A simple message went out at half-time to look after the ball and to stop making stupid passes," the Samoa great added.
"We showed a lot of character to come from 10 points down but we've got some great individual players and we are growing and learning as a team."