Sunderland sporting director Kristjaan Speakman backed former manager Alex Neil in the summer transfer window by bringing in a host of new recruits to bolster the squad.

The likes of Jack Clarke, Ellis Simms, Daniel Ballard, and Aji Alese, among others, came in and the Black Cats chief has made some excellent signings during his time at the club.

He brought in Ross Stewart, Alex Pritchard and Dennis Cirkin, just to name a few, for Lee Johnson last season and they all played key roles in leading the team to play-off glory in League One.

However, it is unlikely that every signing will be a success and Sunderland have had their fair share of brilliant signings and huge flops over the years.

One player the club struck gold with was the signing of Darren Bent from fellow Premier League side Tottenham in the summer of 2009.

Then-manager Steve Bruce heaped praise on the Englishman at the time of the club-record £10m signing, saying: "He's everything I want - good things come to those who wait.

"It has not quite happened for Darren at Spurs. But he has 50 goals in 100 Premier League starts and that speaks volumes about why we are bringing him to the club.

"He's something different - he's got pace, power, he's young, he's English and he gets goals."

There was further praise when putting him in the conversation for an England spot, with Bruce labelling his work rate as "absolutely unbelievable."

Bent had scored 12 goals in 33 Premier League outings for Tottenham in 2008/09 and the now West Brom boss saw enough to convince him that he was worth a club-record fee for Sunderland, which turned out to be a fantastic call by the English manager.

The striker hit top form on Wearside as he plundered an outstanding 24 goals in 38 top-flight outings, whilst also providing four assists for his teammates - scoring 25 in all competitions.

He then enjoyed an excellent first half of the 2010/11 season as he found the back of the net 11 times in 23 games in all competitions - including eight in 20 in the league.

This led to interest from Aston Villa and he eventually completed a £24m move to Villa Park in January 2011, which meant that Sunderland made a 140% profit on the £10m forward and enjoyed 36 goals from him on the pitch in around a season-and-a-half at the Stadium of Light.

Bruce did admit that he felt let down by the player pushing for a transfer away from the club but the money involved and the quality he did provide during his time with the Black Cats still makes him a successful signing in the end, with the manager playing a blinder by snapping him up in 2009.