A competition that has caused Mark Warburton so much frustration in recent weeks continues to prove useful to Rangers.

The Betfred Cup has been the source of much consternation at Ibrox so far this season but Rangers now find themselves in the quarter-finals after they made it five from five in the newly revamped tournament with a 5-0 success over Peterhead.

Like their Group F wins against Annan, East Stirlingshire and Stranraer, victory at Ibrox was achieved with ease by Warburton’s side. The assignments will get more difficult from now on, but Rangers’ sights will be set on the first silverware of the season.

READ MORE: Mark Warburton hopes to add to Rangers squad before Premiership clash with Dundee

After faltering on their return to Premiership action at the weekend, this was the perfect response from Rangers. It wasn’t their toughest test, but it was one they passed with ease.Glasgow Times: Niko Kranjcar finds the top corner with a superb strike, his second goal for Rangers

Warburton bemoaned the Group F schedule as the Gers warmed up for their top flight campaign with a trip to Motherwell and then three low-key encounters against lower league opposition. It wasn’t the schedule he wanted, but it was one that was safely negotiated.

The only thing Rangers could take from those outings, apart from a place in the second round, was match fitness as the Ibrox squad got vital minutes under their belt. The same can be said of this meeting with the Blue Toon.

READ MORE: Mark Warburton hopes to add to Rangers squad before Premiership clash with Dundee

Warburton will not have learned a great deal about how ready his side are to tackle Dundee this weekend, but his players will head to Dens Park another step closer to the levels they will have to quickly reach if they are to challenge in the Premiership this term.

There were a handful of changes from the team that were held by Hamilton on Saturday but the players that needed a game the most were all handed another start as Joey Barton and Niko Kranjcar were joined in midfield by the impressive Jordan Rossiter.Glasgow Times: Jordan Rossiter

The Croatian’s fitness has been questioned in recent days and he was far from his best against Accies. It was no surprise to see him start once again, especially after receiving Warburton’s backing before the game.

His faith would be repaid as Kranjcar completed another hour and cruised through the game. His sharpness may be in question still, but his natural ability certainly isn’t.

The 31-year-old still has some way to go, but he proved what he is capable of when he put Rangers ahead in the first half as he combined with Joe Dodoo and curled a terrific effort beyond keeper Graeme Smith.

It was a moment of magic that got Rangers off and running and it didn’t take long before the win, and their place in the last eight, was all-but secured.

Dodoo and James Tavernier had both seen shots saved by Smith but the former Ibrox shot-stopper had no chance when the ball fell to Clint Hill from a Kranjcar corner. From a couple of yards out, the defender had time to compose himself and convert inside the keeper’s left-hand post.

The job was done for Rangers. Once again, the remaining minutes could be used to top-up their fitness and to attempt to catch the eye.

For those that are looking to break into side, this was an ideal chance to impress. It was one the likes of Lee Hodson, Harry Forrester, Michael O’Halloran and Dodoo all grasped.

The latter duo should have got their name on the scoresheet before the end of the first period but both were denied by Smith as he kept the scoreline respectable during wave after wave of attacks from Rangers.

More goals would come, but they didn’t arrive until the second half as Warburton’s side eased towards the quarter-finals.

O’Halloran, like Dodoo, is vying for a place in the three-pronged Gers attack and he operated across the forward line at various stages. He adds pace and a directness to Rangers, and if he can improve his final ball then he will undoubtedly be an asset this season.

It was his cross from the right that lead to Rangers’ third of the night, with Fiacre Kelleher, the on-loan Celtic defender, only able to divert the ball into his own net.

Things would get worse for Jim McInally’s side, though, and just minutes after Nathan Blockley was shown a straight red for a reckless lunge on Barton, Rangers made it four as Hill headed home from a Kranjcar corner. The Gers’ dominance on the park was now shown on the scoreboard.

It meant Warburton could turn his attentions to Tayside and that signalled the end of the evening for his midfield trio as Andy Halliday, Jason Holt and Barrie McKay were introduced after an hour.

The reshuffle saw Dodoo assume the central role in the Gers’ attack and he soon got the goal his encouraging performance merited as he converted a Tavernier cross at the near post. It was his first strike at Ibrox, and Warburton will hope there is plenty more to come from the former Leicester City kid.

By the time Rangers head to Dundee this weekend, they will know who stands between them and another trip to Hampden in the coming weeks.

Warburton will hope this Betfred Cup outing proves useful between now and the next round, though, as Rangers look to find their stride in the top flight. Once again, he has selection puzzles to solve.