"It's a marriage," she said. "It really is. It takes a long time to gel with a horse."
Some might have given up on Lenamore. Powell talks of him being "difficult" and a "tearaway" in his youth, being a bit "quirky" and a "bad traveller" but the pair have found a happy working relationship over the last eight years and could figure in London.
Teammates Mark Todd and Andrew Nicholson, who are both going to their seventh Olympics, might receive all of the attention and be among the favourites but Powell is a chance and will certainly be relied on in the team's event. She finished 14th in Beijing, the highest-placed rider in the three-day event, and won Burghley in 2010 on Lenamore.
"I think I went into Beijing quite uptight about the whole thing because it was new and different," she said. "I wasn't all that confident with him. I think this time, a lot has happened over the years. The pair of us have grown up a little bit. We are a lot more focused this year. We know each other more.
"I'm very quietly confident. He's in cracking form. As long as his brain space is good."
The venue at Greenwich Park, built around the prime meridian line and overlooking the city, is different to anything riders experience elsewhere and will be a factor. So will the occasion.
Great Britain and Germany will start as favourites in the team's event but the talk around the stables is about how New Zealand are once again a force. Todd's return to the sport after retirement is a big part of that but so is the emergence of the likes of Powell and Jonathan Paget.
"I think we are going into the Olympics with one of the strongest teams we have ever had," he said. "We are always slightly cautious. You don't want to get too cocky. We have been in this position before where we have gone into championships thinking we are favourites and things go wrong. You also need a bit of luck on your side."
Powell probably feels she's due a bit of that.