The U's brought their trip north of the border to a close with a 2-1 win at Berwick, courtesy of goals from Asa Hall and Sean Rigg.
Boss Chris Wilder has been busy in the transfer market so far this summer, bringing in seven players and Lewis believes the trip has proved a great bonding experience.
"It has been a brilliant week, it's important if you have new players to have a week away where everyone is mixing," he said.
"Everyone has enjoyed it and the boys have worked really hard."
On the win against the Borderers he added: "It's a good workout and as always you want to win every game.
"After the first 15 minutes it was only us in it but the tempo wasn't really what we wanted.
"The second half was much better and the goals came."
- Sports & Recreation
- Asa Hall