To give the referee some credit (/an excuse), we've all pretty much immediately agreed on here that the only factor that might have saved the defender from a red is if the GK is getting there first. While it's fairly clear from a side-on camera view, I don't see how on earth it could be clear from the position he was likely to be in - 50 yards back, at a poor angle initially chosen to assess the Chelsea attack.
I still feel like (particularly with VAR available to downgrade if necessary), I would have been inclined to go red if I had to guess, but Tierney didn't have to guess - this is pretty much the AR's call to make. From a side-on view, roughly level with the defender it might(???) not be 100% clear that there is a foul, but once Tierney blows for it, he should be screaming for a red card down the comms.
I still feel like (particularly with VAR available to downgrade if necessary), I would have been inclined to go red if I had to guess, but Tierney didn't have to guess - this is pretty much the AR's call to make. From a side-on view, roughly level with the defender it might(???) not be 100% clear that there is a foul, but once Tierney blows for it, he should be screaming for a red card down the comms.