The former Leeds star got a red card for his reaction to the fourth goal conceded by his team, which came in the 74th minute courtesy of Jayden Stockley - his second of the game.
Pierce Sweeney also grabbed a brace, and Aaron Martin added the fifth in injury time.
League Two
Jennings hits late winner as Tranmere beat Newport to reach League One
25/05/2019 AT 17:01
Enzio Boldewijn got a consolation goal for the Magpies just before half-time.
County are bottom of League Two with just one point from their seven-game campaign so far.
Watch highlights of all Saturday's EFL action at 21:00 on Quest.
League Two
Ref Dean leads celebrations as Tranmere reach League Two play-off final
14/05/2019 AT 08:00
League Two
Paul Scholes resigns as Oldham manager
14/03/2019 AT 17:12