Abject Truro City hit for six as they suffer third successive league defeat (by Rhod Mitchell, West Briton)
Ten man Truro City were given a brutal lesson as they slumped to a third successive National League South defeat after being totally outclassed by the impressive visitors.
Trailing 2-0 at half time, they then had defender Rob Farkins sent off and were fortunate to concede only four more goals as Oxford cruised to victory.
The defeat leaves City 17th in the table, just two points off the relegation places.
He said: "It's a bad day at the office. The worst game since I taken over as manager. I think we were lucky to finish 6-0 because they were the better team.
"What disappointed me most was that at 3-0 down and down to ten men we gave up, that's the biggest thing that hurt me."
And City fans should expect some coming and goings over the next few days.
Tully said: "There will be movement of players, there are certain players who cannot play this level and we need to get ones who can."
He said both himself and his management team, as well as the players, also needed to look at what they were doing.
City had to endure a chastening first half as they struggled to cope with the movement and pace of the visitors.
It took Oxford only six minutes to take the lead, with Omari Sterling James allowed far too much space in the right hand channel before finding the far corner of Martin Rice's net with a powerful low drive.
And it became 2-0 after 19 minutes when a simple long ball put Bradley Bubb clear and he easily beat a helpless Rice.
City struggled to create chances, with Arran Pugh unable to get a header on Rice free kick and Craig Duff forcing a good save from Laurie Walker their best efforts.
In contrast, an excellent Oxford side posed a constant threat and could easily have had a third before the break.
At half time, Tully brought on Dan Green and Les Afful for Jake Ash and Conor Riley-Low, but any hopes of a revival were soon ended as Farkins saw red five minutes into the half.
Chaisng back after losing the ball Farkins brought down Reece Fleet inside the area and as "last man" had to go.
Substitute Vinny Mukendi converted the spot kick to make it 3-0 and effectively end the game.
Oxford were in total command, as Mukendi struck twice more to complete his hat-trick in a 11 minute spell, with Luke Coluson ending the rout right on time with another penalty, after Shane Krac had brought him down, to end a miserable day for the home club.
It will now be a big test for manager Tully and his players starting with Saturday's trip to ninth-placed Eastbourne Borough, to try and turn the season around and it should make for fascinating viewing.
TRURO CITY: Rice; Farkins, Ash (Green h-t), Pugh; Dawson, White, Krac, Brett, Riley-Low (Afful h-t), Wright (Cooke 57), Duff. Subs (not used): Yeoman, McHale.
Yellow cards: Pugh, White, Wright, Krac.
Red card: Farkins.
OXFORD CITY: Walker; King, Lapoujade, Del Alamo, Arzamendi, Santiago, Coulson, Fleet, Bubb (Mukendi 20), Lafuente, Sterling, James. Subs: Benjamin, Henderson, Pifarre.
Yellow cards: Fleet, Lafuente.
Goals: Sterling James (6) 0-1, Bubb (19) 0-2, Mukendi (52 pen) 0-3, Mukendi (55), 0-4, Mukendi (63) 0-5, Coulson (90 pen) 0-6..
Referee: Savvas Yianni (Weston-Super-Mare.