Few gave Ireland a chance in the two-match series, but Lorcan Tucker's side humbled India twice in three days, spoiling Shreyas Iyer's debut series as India's 20-overs captain.
"There's a little bit of disbelief," Ten Doeschate told reporters after Ireland edged them out by one run on Sunday.
"It's also very hard to be critical of guys who have just won a World Cup. We've been outdone or outsmarted by a team who just did the basics very well."
The former Dutch player hailed Ireland's inspired display but felt the Indian batters failed to get used to conditions at Stormont.
"Firstly, credit to Ireland and secondly, the learnings for us in terms of being able to adapt to different conditions," he said. "That's probably the biggest takeaway from this."
Coming off the flat pitches and short boundaries in the Indian Premier League, Iyer and his men struggled on a spicy pitch with bigger square boundaries.
Ten Doeschate acknowledged his batters failed to make the transition.
"That was essentially our undoing," he said. "It's something we spoke about before, but we just didn't address it well enough out in the middle."
"We're probably too used to a tempo and style where you can hit sixes more freely. I think this will be the case when you go to England as well, you know, maybe slightly quicker wickets, maybe slightly less wind, but we're going to have to adapt and be a lot smarter about how we'd like to play if we're going to get wins there."
India's next assignment is a tour of England featuring five T20 and three one-day internationals, starting July 1st.