Stephenson is currently on-loan at Dundee United in Scotland.
He recalled to the Liverpool Echo: "Who was the most difficult opponent in training? Most to be fair, if I'm being honest!" laughs Stephenson, who is currently on a season-long loan at Scottish Premiership side Dundee United.
"The quality in the first team is outrageous really, isn't it? You train against Luis Diaz, Fabio Carvalho was still there, those players were playing down the left and are running at you in training... I would look forward to it but think 'jeez, this is going to be a hard session!'.
"But it stands you in good stead because now I'm thinking if I can get through a 90-minute in-house game against Luis Diaz, then I can have full confidence playing against anybody as he's one of the best wingers in the world.
"I spoke to the manager when we were out in America. He said he'd been impressed by me and spoke about last season's loan and what the level was like there. He was really good with me."
Stephenson said of his positional switch: "Everybody at Liverpool thought I was best going on loan as a midfielder and Barrow saw me as one," he says. "Then about three weeks into the spell both right-backs got injured and the manager said 'look, I've seen you play right-back before, do you fancy it?' and I ended up playing there, had a few good games and went from there.
"I played at right-back in pre-season for Liverpool, and Dundee United have brought me in as a right wing-back. I wouldn't say right-back was my first position but I've learned a lot about it in the last couple of years to know what I am doing."