Marsch is closing in on a year in charge at Elland Road after replacing Marcelo Bielsa in February 2021 and his side sit 15th in the Premier League, two points above the relegation zone, ahead of the latest round of fixtures.
Leeds were in an almost identical position when Marsch was appointed – two points above the bottom three in 16th place – and avoided relegation on the final day last season by winning at Brentford.
When asked for evidence of his side’s progress before their New Year’s Eve game at high-flying Newcastle, Marsch said: “The behaviours of the players and the development of the players.
“There’s a lot of guys I think who have developed a lot since I’ve been here.
“I think Robin Koch right now is playing the best football of his career, I think Pascal (Struijk) is, Tyler Adams is, I think Marc Roca is, I think Rodrigo is, I think Sam Greenwood is, I think Cree Summerville is.
“So the guys who have been a really big part of how we’ve continued to evolve are showing they’re in really good phases of their career and we’re going to continue to make them better.”
Leeds, who have beaten both Chelsea and Liverpool this season, were out-classed but far from disgraced on Wednesday night in a 3-1 home defeat to defending champions Manchester City.
Leeds’ progress under Marsch will be sorely tested again on Saturday at Newcastle, who have emerged as genuine Champions League contenders under Eddie Howe and their new owners.
Marsch said Howe had “done an amazing job” but pointed out that the Premier League, and European football in general, was not a level playing field.
He added: “We all know that in this world of football, it’s something that’s different to American sports.
“We have salary caps (in the US) and everyone has a chance when the season starts. I’m sorry, but the way that European football works, that’s just not the case.
“And so how do you build? Well one way is a process and continuing to invest every penny the right way, which we are trying to do.
“And another (way) is a massive influx of money. Take Chelsea 25 years ago, take Newcastle now, take Man City 15 years ago, I mean it’s a difference-maker.
“But we like us. We like who we are. We like our identity. We like the mentality we’ve created. We like us, so we’re going to go on building in our own way.”
Adams is available for the trip to St James’ Park after suspension and Marsch hopes Summerville (foot) and Jack Harrison (adductor) will also be back in contention.
But Patrick Bamford, who had groin surgery during the World Cup break, will not return to full training until next week.