NEWCASTLE UNITED have agreed a deal to make Borussia Dortmund midfielder Mikel Merino their fifth summer signing, but Rafael Benitez has admitted the Magpies have to move players out before they can make further additions.

Newcastle continued their pre-season preparations with a resounding 4-0 win at Bradford City this evening, with new signing Jacob Murphy scoring a second-half double to accompany further goals from Dwight Gayle and Aleksandar Mitrovic.

While the Magpies were cruising to victory at Valley Parade, Merino was completing a medical on Tyneside to enable him to finalise his move from the Bundesliga.

The 21-year-old will initially move on a season-long loan, although Newcastle have also agreed a compulsory clause that will see them complete a permanent transfer worth around £6m next summer no matter what Merino does over the course of the next 12 months.

The Spain Under-21 international joined Borussia Dortmund for £3.1m last summer, and made nine senior appearances for the German side last season.

“It's not quite done yet, but we're working to try and finalise everything,” said Benitez. “I’m quite confident that we'll do it.

“Hopefully, it will get done and we will have a player with quality, who can help us in the middle of the park.”

Merino joins Murphy, Florian Lejeune, Javier Manquillo and Christian Atsu on Newcastle’s list of summer signings, but while Benitez remains keen to make further additions, the Magpies manager admits the size of his current squad is making it difficult to conduct business.

Newcastle currently boast around 30 senior players, and will have to move on the likes of Tim Krul, Karl Darlow, Achraf Lazaar, Henri Saivet and Emmanuel Riviere before they can make significant improvements to their squad.

“Every manager wants to sign more players, and that is especially important when you are promoted from the Championship to the Premier League,” said Benitez. “It's maybe not the same when you're already in the Premier League and you need three or four maximum.

"When you are changing division, it's more difficult and you have to bring more players. But we have a problem, which is obvious, which is we already have too many players.

“We have to move players out if we want to move players in. That's something we have to manage between now and the end of the window.”

Lejeune was the only new face to start tonight’s game, partnering Ciaran Clark at the heart of defence in the absence of the injured Jamaal Lascelles. Murphy came on at the start of the second half, along with full-back signing Manquillo.

The most notable absentees were Darlow and Krul, with the goalkeeping duo clearly not playing a part in Benitez’s plans for next season.

Jonjo Shelvey will be one of Newcastle’s most important performers, and the midfielder was the stand-out performer as the Magpies enjoyed a useful test against League One opposition.

Admittedly, Shelvey was afforded the kind of midfield freedom he will not be granted in the Premier League next season, but he still caught the eye as he constantly demanded possession and sprayed a series of pinpoint long-range passes into the feet of his side’s forwards.

Matt Ritchie almost profited from one of Shelvey’s long balls in the fifth minute, only to fire a low shot straight at Bradford goalkeeper Colin Doyle, and Shelvey had the ball in the net midway through the first half, only for his effort from an acute angle to be ruled out for a handball earlier in the move.

Ritchie clipped the top of the crossbar with a miscued cross towards the end of the first half, and having dominated the opening period, Newcastle’s bright play was finally rewarded with two goals in the space of a minute at the start of the second half.

Gayle claimed the first, stealing ahead of his marker to steer home Christian Atsu’s low cross from the left-hand side.

Gayle then turned provider moments later, teeing up Murphy, who turned neatly inside his marker before rolling home his first goal in a black-and-white shirt. It was a landmark moment for the childhood Newcastle fan, who was immediately engulfed by his team-mates.

Second-half substitute Mitrovic claimed Newcastle’s third goal with 14 minutes left, slotting home from inside the six-yard box after fellow replacement Rolando Aarons had burst past his marker on the left-hand side, and Murphy scored his second goal of the night to complete the scoring, controlling a miscued header on his chest before dispatching a crisp half-volley into the net.

The £12.5m summer signing will have much stiffer tests in the weeks and months to come, but he has nevertheless proved he is capable of providing a welcome goalscoring threat from the wide positions.

“It was good,” said Benitez. “The main thing was improving the players' fitness and their understanding between each other. We created some good situations and also defended quite well.

"It was what we were trying to do, although there are still things we are trying to improve. But at least you could see a team that were trying to do the movements that we were practising in the training sessions.”

Bradford (5-4-1): Doyle; McMahon, Knight-Percival, Kilgallon, Vincelot; Gilliead, Reeves (Devine 72), Law, McCartan; Jones.

Newcastle (4-2-3-1): Elliot (Woodman 61); Yedlin (Manquillo 46), Lejeune (Mbemba 61), Clark (Saivet 76), Dummett (Gamez 61); Shelvey (Aarons 61), Hayden (Colback 76); Ritchie (Murphy 46), Perez (Diame 46), Atsu (de Jong 61); Gayle (Mitrovic 61).