The Championship side knocked their Premier League opponents out of the competition with a 2-1 victory tonight, despite the manager making 10 changes to his side for the match.
Howe told BBC Sport: "I thought the lads were excellent. The guys that came in, it's never easy but they were superb and I'm delighted for the fans and the club, we are in unchartered territory.
"The last two years have been so successful that we have a good mentality in the dressing room. It showed again because when we conceded we went up the other end to score again quickly.
"They are a good side and you feared they may get a chance. The strength of character to score again really pleased me. The players are hard working and they deserve it."
The result comes just three days after Bournemouth beat Birmingham City 8-0 in the league.