The former Gunner said as quoted by the Glasgow Times: "Both Tierney and Robertson are terrific players. They're both players that I could sit and watch all day.
"Tierney, in particular attacking wise, is so effective and is pivotal to what Arsenal are trying to achieve or have achieved this season. His consistency is very good.
"Defensively, I think the game has changed where full-backs are asked to do a lot more work going forward which takes away from the defensive work but he's still strong defensively. But his attitude is spot on – he wants to win which is what you need."