Sunderland concluded their pre-season schedule with a heavy defeat against non-league Hartlepool United on Tuesday evening. 

Tony Mowbray opted to make 11 changes to the side that had started against RCD Mallorca at the weekend and a youthful squad would struggle immensely at Victoria Park, as the Black Cats suffered a shock 5-2 loss. 

Seasoned pros such as Lynden Gooch, Danny Batth and Alex Pritchard would feature from the start, while youngsters such as Chris Rigg, Nectarios Triantis, and Abdoullah Ba were given the full 90 minutes. 

It took just three minutes for the hosts to take the lead, as Batth's slack pass from the back fell to Chris Wreh in the box, and he finished with aplomb. 

Mowbray's side were level fewer than 10 minutes later, as Pritchard was fouled on the edge of the box, and he picked himself up to curl the free-kick into the top corner. 

However, a nightmare two-minute spell saw the Black Cats go 3-1 down, with French midfielder Anthony Mancini grabbing both. 

He was first left unmarked in the box to sweep home a first-time finish before Rigg gifted him possession straight from kick-off, which he took full advantage of by curling into the bottom corner from just outside the area.

Sunderland were guilty of missing a number of chances to get back into the game, with Ba particularly wasteful when played in on goal on two separate occasions, but Mowbray was able to stem the tide by switching to a more familiar four-at-the-back formation. 

It seemed as if the Championship outfit would be able to kickstart a comeback against their recently-relegated hosts when a clever through ball from Triantis allowed Jewison Bennette to curl home for 3-2, but it was Hartlepool who kicked on from there. 

A clumsy challenge from Gooch saw John Askey's side gifted a penalty and summer signing Emmanuel Dieseruvwe step up to send Anthony Patterson the wrong way for 4-2 on 76 minutes. 

And Joe Grey would wrap things up for the hosts when another shocking pass from the back couldn't be collected by Patterson, leaving the striker with the simple job of tapping the ball into the empty net. 

Despite the changes that Mowbray made, from both a tactical and personnel perspective, it is worrying for the squad to suffer such a heavy defeat against non-league opposition so close to the new campaign. 

The Black Cats kick off the Championship season against newly-promoted Ipswich Town at the Stadium of Light on Sunday afternoon.