The 18 year-old was loaned out by Spurs to Portsmouth this summer as he looks to further his development on the south coast.
Scarlett has started seven League One games for Portsmouth so far, but played the full 90 minutes for the first time against Ipswich Town last weekend.
Cowley was glad to see Scarlett stay on the pitch for the full 90 minutes in the 3-2 defeat to Ipswich Town.
While the Portsmouth boss thinks highly of Scarlett for playing with the same intensity throughout the full 90, he also got a bit nervous as the Tottenham loan star is a key player for them.
Speaking to The News, Cowley said: “It was great for Dane to play 90 minutes at Ipswich.
“That was his first 90 and he was able to keep his intensity, which was making me a bit nervous because he’s very precious to us!
“We like to look after him.”
Scarlett has four goals and two assists to his name so far for Portsmouth, but he has not scored in the league since early September and he will be looking to rectify that this weekend when Pompey take on Fleetwood Town.
