Liverpool won 4-0 thanks to goals from Diogo Jota, Trent Alexander-Arnold, Fede Chiesa and Jayden Danns.
Slot said afterwards: "Credit to them, I think they showed their style of play, which is a big compliment.
"They played the same style as they always play. In the end, of course, the difference in quality makes a big difference for us, but compliments to them with how they showed up today."
On Rio Ngumoha being Liverpool's youngest starter in the FA Cup, Slot said: "He did well. There were a few moments where the fans could see why we think he's a talent. He is good in one-v-one situations.
"He showed a bit more in the first half than in the second half. It is nice to get your debut and get the win. It is a special day for him."
On Trent Alexander-Arnold's performance, he said: "Trent didn't have his best game against Manchester United, but for the rest of the season he has been so good for us - I liked his performance today.
"Our fans have always given him a lot of support. He didn't play well once, but fans reacted to that. If Trent just plays what we expect from him, then he gets support."
On Federico Chiesa's first goal for Liverpool, Slot added: "It is definitely a good first step, but as much as I liked the way Accrington Stanley played we have to take into consideration that we're talking about League Two level.
"It is good to have him back on the pitch. He was a threat, but let's not get carried away."