Moises Caicedo struck late to earn Chelsea a point, though Colwill insists the visitors were worthy of more.
He told chelseafc.com: "I think the team are very frustrated. Where we are in the season, the football we’ve been playing, like today at times, we deserve to win most games,' said the centre-back.
"I want to win every game so I was bit disappointed yesterday that we didn’t. It was obviously a tough one out there and they had threats and that’s how they scored.
"We know what we’re building, we know how good we are, how good we can be and how good we’ve been this season.
"At times in this game we played good football, created good chances, but if you don’t take the chances it keeps them in the game and they get a sniff. That’s what happened yesterday."
Colwill, 21, continued: "I’m a bit frustrated because I went into the game to get three points, and it’s always frustrating when you don’t win the game. I thought we played good stuff and created good chances that on another day we might take.
"The finishing touch was missing yesterday but I wouldn’t say it’s been missing this season. I think we have adapted this season really well.
"We played some great stuff yesterday, starting from the back and building up. Obviously they knew how to stop us from watching our previous games, but we adapted to that too."
On Caicedo's strike, Colwill also declared: "It was definitely huge. You’ve got two ways to react, you either put your head down or you get on with it and try to get the equalising goal, which obviously we did.
"Moi is an amazing player and we’ve got so many of them that, when you’re struggling in a game or when you’re not scoring, they pull out that magic.
"We’ve been behind already this season and we know you’ve got to react fast. We know we’re a good team, we believe we’re going to create more chances to score no matter the time in the game and that happened yesterday."