Magpies duo Sean Longstaff, and Freddie Woodman, are understood to have been the focal point for scouts at the game, with Manchester United also running the rule over the pair.
Both players have Scottish top flight experience; goalkeeper Woodman with Aberdeen and Kilmarnock while midfielder Longstaff also had a spell at Rugby Park.
Longstaff and Woodman are still to agree new contracts with the St James’ Park side and other clubs are keeping tabs on the highly-rated pair, with their contracts expiring next summer.
The Hoops launched a late bid to lure Woodman to Parkhead in January, but the England Under-21 ‘keeper completed a loan switch to Aberdeen. Longstaff has also been linked with Rangers.
Longstaff and Woodman played the full 90 minutes for the Magpies’ second string side but the Saints recorded a narrow 1-0 win, Longstaff passing up a great opportunity to level early in the second half.
News of the scouting mission comes as it emerged earlier today that Celtic have identified Wigan’s Nick Powell as a potential signing in January.
But Brendan Rodgers’ side will face stiff competition from Brighton for the former Manchester United youngster.