The 23-year-old joined the Reds from Hull City earlier in July, and linked up with his new team-mates ahead of their pre-season tour of Germany.
But Robertson replaced the Spaniard after the break, and produced an impressive 45-minute display at the Olympiastadion.
And speaking to LiverpoolFC.com after the victory, the Scotland international reflected on a “brilliant” debut.
“It was my first game since the start of May so it was good to get rid of the cobwebs,” he explained.
“To pull on this shirt and play with the boys was an honour. Hopefully there’s many more to come.
“The boys did well in the first half and we had to wait patiently on the bench. But in the second half, I thought we controlled the game as well.
“The lads all dug deep and we got what we needed out of the game.”
Robertson certainly didn’t look out of place at left-back, and provided some promising crosses from the flank, including one that could have seen Mohamed Salah score a tap-in.
That he was so comfortable on his first outing for the Reds, after only a handful of training sessions under Klopp, is encouraging.
And Liverpool‘s new No. 26 believes he is settling in well, and hailed his new supporters as “different class” on Saturday night.
“The boys have been together longer than a few of us who came back late. We’re gelling in,” he added.
“Training has been intense, it has been good. It’s good to get a game, everyone enjoys playing games. It was good to come away with a win and a clean sheet.
“The Hertha fans were brilliant and the Liverpool fans in the corner were different class throughout the game.
“It was a good atmosphere to play in, a great stadium and they’re the games you want to play in.”
Setting his sights on the role of first-choice left-back, he will be looking to build on this bright start and relegate James Milner to a watching brief on the bench.