Cornish Pirates coach Ian Davies says Saturday's trip to London Welsh will be one of their toughest games this term.
Davies expects the Exiles, who were relegated from the Premiership last campaign to be a cut above anything his side has faced so far this season.
"As an ex-Premiership team, they'll be ruthless. We've got to be on the money," he told BBC Radio Cornwall.
"They've recruited really well and retained a lot of the Premiership side. They're got a really strong squad."
London Welsh are top of the Championship table with four wins out of four, while the Pirates are in fourth place.
Davies added: "They've got guys with international caps and lots of Premiership experience, and are blessed with really powerful set-pieces, and Gordon Ross pulls the strings at number 10.
"I would say they're playing a Premiership game within the Championship. They want to get set-piece dominance and get their big ball carriers over the gain-line, and then kick penalties or score tries once they've worn you down.
"If you've played Leicester and Saracens then - no offence to our players - the intensity of that is higher than that of Pirates or Moseley or whatever, so those players have that belief that they can play at a higher intensity.
"We'll try to keep the ball alive and keep the tempo high. We don't want to allow them to have a stop-start game - we have to be switched on in defence, but also in attack so we can exploit any defensive gaps.
"We're going there to play - we've not made too many changes to the side and it's a chance to play on a very good surface against one of the best sides in the league."
Centre pairing Tom Riley and Rheon James return to the starting line-up at the Kassam Stadium, while Kieran Hallett will captain the side from fly-half with Tom Kessell inside him at scrum-half.
Joe Atkinson starts at open-side flanker and a new-look front-row sees hooker Tom Channon team up with props Shane Cahill and Peter Joyce.