Bath took full advantage of weakened Newcastle's injury woes as they eased to a six-try victory at Kingston Park.

Hooker Tom Dunn went over twice, while prop Henry Thomas, number eight Zach Mercer and replacement hooker Jack Walker also crossed the whitewash.

Falcons, who ended with a late penalty try, scored first-half tries via prop Trevor Davison and centre Tom Penny.

But their poor run of just one league win in two months always looked set to continue when they were forced to make three late changes.

Fly-half Joel Hodgson, scrum-half Michael Young and bench replacement Logovi'i Mulipola all had to withdraw, meaning recalls for Brett Connon and Sam Stuart.

Bath also had a late withdrawal when they lost Wales international fly-half Rhys Priestland in the warm-up after aggravating an existing shoulder injury - and his replacement Tian Schoeman went off before the break, forcing Josh Matavesi to move from inside centre to 10.

But the visitors made light of it for a first win at Kingston Park in six seasons - and a fourth win in five games to rise two places to eighth in the Premiership, level on points with seventh-placed Newcastle.

Underhill was making only his second Bath appearance after being ruled out of England's Six Nations campaign with a hip injury.

Newcastle have another home game next Friday night against Wasps (19:45 GMT), while Bath are back in action the following day at home to bottom club Worcester.

Newcastle director of rugby Dean Richards:

"We could sit here and make all the excuses about not having been able to train much since Christmas, and it is a factor. But we can't use it as an excuse this week because we've had a full training schedule,

"We've just not produced on the day. We weren't at the races, and Bath are a good team. Against a side with a near-international back line and a good pack we've just got to be better than that.

"It was the most error-strewn game we've played this season. The needless penalties just kept on mounting. That put us under a lot of pressure, and we didn't defend particularly well."

Bath boss Stuart Hooper told BBC Radio Bristol:

"The tries were scored by the forwards from the position that the backs put us in. We just came here with a plan and executed."

Bath hooker Tom Dunn told BBC Radio Bristol:

"It's always pleasing to score tries but it's not what I build my game on. It's a case of trusting each other and staying in the system. And, if you get everything right, all the little things add up.

"I'm just very pleased to have the opportunity to be playing right now. This is just the result you need ahead of a seven-hour journey home."

Newcastle: Penny; Tait, Wacokecoke, Burrell, Carreras; Connon, Stuart; Davison, McGuigan, Tampin, Peterson, Barry, Graham, van der Walt, Chick.

Replacements: Maddison, Cooper, Daniels, Robinson, Hardie, Schreuder, Vuna, Joel Matavesi.

Bath: De Glanville; Cokanasiga, Joseph, Josh Matavesi, McConnochie; T Schoeman, Spencer; J Schoeman, Dunn, Thomas, McNally (capt), Stooke, Reid, Underhill, Mercer.

Replacements: Walker, Cordwell, Judge, Ellis, Staddon, Fox, Clark, Rokoduguni.

Referee: Ian Tempest.