Reliable BBC journalist David Ornstein has confirmed Arsenal’s opening bid for Celtic left-back Kieran Tierney has been turned down.

GLASGOW, SCOTLAND – APRIL 23: Kieran Tierney of Celtic and James Tavernier of Rangers compete for the ball during the Scottish Cup Semi-Final match between Celtic and Rangers at Hampden Park on April 23, 2017, in Glasgow, Scotland. (Photo by Mark Runnacles/Getty Images)

As we reported on yesterday, claims emerged from Scotland over the weekend that Arsenal had their first £15m bid for Kieran Tierney rejected by Celtic.

These reports have been confirmed by David Ornstein, who adds that there is ‘optimism’ that an agreement will be reached. Ornstein also clarifies that personal terms aren’t expected to be a problem, so it’s just about convincing Celtic to sell.

The Daily Record now report Arsenal are expected to come back with a £20m bid in the next 48 hours, which they believe will be enough to complete the signing. On the other side of things, Celtic want closer to £25m, so there’s still some negotiating to do.

Signing Tierney would be an excellent start to Arsenal’s summer business. The 22-year-old is a very highly-rated prospect in a position the club need to strengthen, and opposite Hector Bellerin he could help the Gunners lock down the full-back positions for years to come.

In turn, that should help Arsenal’s endless pursuit of centre-backs and a strong defence. Central defenders should be much keener to join knowing that they’ll have two capable full-backs around them for the foreseeable future.

Look at Liverpool. Which centre-back wouldn’t want to join Andy Robertson, Trent Alexander-Arnold and Virgil Van Dijk in a back-four?

Arsenal are lacking a Van Dijk, but we have to take things step-by-step. Tierney, Bellerin and Koscielny for one more season would be a good start.