There were a mere 11 points separating the two teams over the three games in Brisbane, Melbourne and Sydney, with the third Test at the weekend decided by a single point in favour of the Wallabies at 20-19.
Howley took over as coach for the pre-tour game against the Barbarians and in Australia while Warren Gatland was recovering from the injuries he sustained in a fall at his holiday home in New Zealand on Easter Monday.
Although Gatland arrived in Australia in time to watch the second and third Tests, he left the coaching duties in the capable hands of Howley.
"I thoroughly enjoyed the opportunity and challenge that presented itself over the last three or four weeks. It was everything I expected it to be - challenging," Howley said.
"Without the support of (coaching staff) Shaun Edwards, Robin McBryde and Neil Jenkins, we might not have got so close. They have all been fantastic.
"We have all got a lot to thank Warren for because he brought us all in and has given us our head on several occasions over the last three or four years. Without that experience we would have been a lesser side for it.
"The experience the players have had in Australia will help us to improve. Our attitude and effort got us so close to beating the Wallabies and we have left a mark here that we are quite proud of."
Having got back to within a point of the Wallabies in the second half in Brisbane, Howley's side took the lead four times in the second Test in Melbourne. They then twice hit the front in the second half in Sydney, only to fall to a Berrick Barnes penalty four minutes from time.
So how does Howley reflect on a series in which his side were beaten 27-19, 25-23 and 20-19?
"Can we play them again next week please?" he quipped after yesterday's [Saturday] match.
"I am immensely proud of this group of players and there are a lot of good ingredients that have come out of the last three weeks that should make them feel pretty proud of their efforts.
"There were moments in the match we could have controlled better. But those moments will come again in the Autumn Series and the Six Nations and hopefully we will have learned how to make the most of them.
"A lot of things happened in the last 10 minutes and it was a new experience for a lot of these young players who hadn't played in a three-Test series before. It has been a fantastic learning curve for us discovering how to get back up for games week in, week out.
"The respect we have had over here has been great, but this Welsh team is better than that. We want to win international games and the one thing you need to do when you gain respect is come to places like Australia and win."