Arsenal reinforce backline by signing Tierney for reported £25M

It went down to the wire, but Arsenal were finally able to complete the signing of Kieran Tierney from Celtic on Thursday, thus ending one of the longest-running transfer sagas of the summer.

The Gunners, who had a pair of bids for the Scottish left-back turned aside earlier in the window, reportedly forked over £25 million to seal the deal.

Tierney, 22, inked a long-term contract with the club and is expected to earn £75,000 a week at the Emirates.

"We're delighted Kieran is joining us. He's a very talented player who will continue to improve," manager Unai Emery said. "He increases our options defensively and I look forward to him joining our group."

Prior bids of £15 million and an incentive-laden £25 million had been rejected by Celtic, who reportedly weren't keen on the payment structure of the latter offer. While Arsenal's third attempt featured the £25-million price tag, a more traditional payment plan was key in bridging the gap between the two clubs.

Tierney, who won five league titles with Celtic, hasn't played since undergoing a double hernia operation in May.

He passed his medical Thursday, though, and will reinforce an area of obvious need for Arsenal once he returns to action. The Scottish international should get the nod over both Nacho Monreal and Sead Kolasinac as the starting left-back for Emery's side.