The Durham County graduate became the latest player to get his chance at the top of the order, with Dom Sibley, Rory Burns and Haseeb Hameed all failing to keep their place in the vexed position.
Lees lined-up against a Cricket West Indies President's XI in Antigua, and put on a classy showing having scored 65. The tourists finished the opening day on 251/4.
The 28-yaer-old channelled traditional opening methods of caution and application as he occupied the crease for five hours and faced 214 deliveries.
Zak Crawley was far more aggressive in his approach and scored 62 runs in less than half the time. Captain Joe Root also produced a well-oiled performance as he scored 54 from 105 balls.
Despite taking his time, Lees did the job he was asked to do and will make his Test debut at the Sir Vivian Richards Stadium better for the experience.
Lees was largely untroubled in his lengthy stay, Raymon Reifer summoning the best of three lbw appeals when he was on 43, and hit the ropes on six occasions when the bowlers strayed.
Surprisingly, given his careful approach, he allowed himself one real flourish when he swung hard at spinner Bryan Charles and plonked him for six over long-on.
Charles took his time exacting revenge, but eventually removed the Yorkshireman midway through the final session, bowling him round his legs on the sweep.
Crawley was left impressed with his teammate's performance saying: "Leesy played really nicely at the top, it wasn't easy to score and they bowled better at him than me actually.
"I've always rated Alex, always thought he was a really good player. He's got a great temperament for this level and it doesn't seem like much fazes him.
"He's really good to bat with in the middle, really calm and up for quite a chilled atmosphere. I think he'll do well at this level.
"He puts them under pressure in slightly different ways to me so it works quite well. He'll take a lot of confidence into next week from that because time in the middle is invaluable."