Not his most eye-catching performance, but quietly effective.
I wouldn't blame him for not being at his best - he's played a whole lot of football lately, and the defence behind him wasn't what he's most used to and comfortable with.
For what it's worth, I don't think the left-back issue is specifically a Gomez or a Cancelo problem. I think it's a general inverted left-back problem. A big part of Jack's game is dropping deep to get the ball and then driving forward with it, ideally pretty centrally. He'll hold the shape high and wide on the wing if you tell him to, no problem, but if you want to see him playing his most exciting and dangerous football then you have to give him that space to move into.
But when the left-back inverts, that means he's occupying the space Jack gravitates towards, and if Jack still tries to go there they get in each other's way and our left channel is open for the opposition. So Jack plays high and wide and does his best but that's not really his game.
I think it might be a potential problem with the inverted full-back system generally. Perhaps a little harder to see on the right because Mahrez doesn't drop so deep, and is more likely to do his cut in to a central position higher up the pitch. But Mahrez has had his inconsistent performances this season too, and I wonder if they correlate with us having an inverted right back?
(This is one of a few reasons why I think using Stones to push forward into midfield from central defence is a better strategy than inverting a full-back.)
Anyway, I also wouldn't be surprised if his instructions yesterday focused on playing a little safe, retaining the ball and being patient. We don't have a lot of left-wing options - if Phil had been fully fit I think Jack would have been rested completely yesterday - so it's important to conserve his energy and avoid injury, and if he protects the ball it helps us play a bit safer, avoid counter attacks, and keep the whole team in as low a gear as possible while still getting the job done.
Our squad is small and there's a lot of games being played in quick succession, we've got to be smart about when we need to go all-out and when we can afford to ease off the accelerator.