Falcons keeps clean sheet
Radwan's treble, plus tries from captain Mark Wilson and former England star Toby Flood, gave the Tynesiders their fourth bonus-point win of the pool stage, and their second win over Enisei in seven days.
The Falcons were already assured of a home quarter-final before kick-off, but didn't take their foot off the pedal in the Georgian capital, despite starting the game into a strong wind.
Although Federico Gilberti impressively gave Enisei the lead, touching down despite colliding with the goalpost, Newcastle soon scored two tries in two minutes. Captain Mark Wilson was driven over from a maul, then Radwan showed quick feet to slalom through three defenders.
Flood was then central to another quick two-try burst, scoring the first after Sam Lockwood's line break, then creating the second with a delightful show-and-go to set up Radwan.
There was no addition to the 26-7 half-time score until Anton Sychev's pick-and-go try for Enisei after 63 minutes. Radwan then completed his hat-trick before a late Russian consolation through Mikheil Gachechiladze.
Teeside flyer Radwan had also scored a treble in last Sunday's 64-7 triumph over Enisei at Kingston Park. His personal points haul for the campaign now stands at 50.
Tries: Giliberti, Sychev, Gachechiladze
Cons: Budychenko 2
For Newcastle Falcons:
Tries: Wilson, Radwan 3, Flood
Cons: Flood 4
Enisei-STM: 15 Richard Kingi, 14 Federico Giliberti, 13 David Kacharava, 12 Dmitrii Gerasimov, 11 Jurijs Baranovs, 10 Aleksandr Budychenko, 9 Konstantin Uzunov, 8 Maxim Gargalic, 7 Vitalii Orlov, 6 Mikheil Gachechiladze, 5 Viacheslav Krasylnyk, 4 Uldis Saulite, 3 Evgenii Pronenko, 2 Shamil Magomedov, 1 Sergey Sekisov.
Replacements: 16 Nazir Gasanov, 17 Azat Musin, 18 Jake Grey, 19 Anton Sychev, 20 Nikita Churashov, 21 Evgeny Nepeivoda, 22 Dmitriy Simonov, 23 Dmitry Gritsenko.
Newcastle Falcons: 15 Simon Hammersley, 14 Zach Kibirige, 13 Tom Penny, 12 Toby Flood, 11 Adam Radwan, 10 Craig Willis, 9 Michael Young, 8 Ryan Burrows, 7 Simon Uzokwe, 6 Mark Wilson, 5 Glen Young, 4 Calum Green, 3 Jack Payne, 2 Ben Sowrey, 1 Sam Lockwood.
Replacements: 16 Jamie Blamire, 17 Rob Vickers, 18 Trevor Davison, 19 Santiago Socino, 20 Callum Chick, 21 Sam Stuart, 22 Cameron Cowell, 23 Joel Hodgson.
Referee: David Wilkinson (Ireland)
Assistant referees: Kieran Barry (Ireland), Chris Harrington (Ireland)
TMO: Kevin Beggs (Ireland)