# [Husk], 5 bytes

    €¹tẊ-

[Try it online!][TIO-kzs4tfha]

[Husk]: https://github.com/barbuz/Husk
[TIO-kzs4tfha]: https://tio.run/##yygtzv7//1HTmkM7Sx7u6tL9//9/tImFjrmhjqGRgY6hpaGOsaGhjqmBUSwA "Husk – Try It Online"

Get the pairwise differences (```Ẋ-```), remove the first one (```t```), and check if this is an ordered sublist of the input (```€¹```).  
Of course, it needs to be a *prefix* of the input (rather than a sublist at any other position), but I think this should be ensured since the input is increasing.