The 21-year-old Spieth's brilliant wire-to-wire win at Augusta shot him up to world number two behind top-ranked 25-year-old Rory McIlroy.
Between them, the pair have won the last three majors, with Martin Kaymer winning last year's U.S. Open at the age of 29.
World number five Day is the next best 20-something after McIlroy and Spieth in rankings and is desperate to keep pace with the young guns.
“I want to be up there with him. That's what I want to do,” Day said in quotes published by Australian Associated Press.
“To watch (Spieth) play so well and to watch Rory play great and really keep that competitive edge and results up is amazing.
“I know it's tough to do but it is something we are all striving towards even more now.”
A raft of 20-somethings are knocking on the door of the top 10, including world number 13 Rickie Fowler (26), 14th-ranked Patrick Reed (24) and 15th-ranked Japanese Hideki Matsuyama (23).
“Our generation is strong. It has taken over now,” added Day, who has had a couple of near-misses at the Masters.
“Hopefully we can all continue to play well for many years to come and win lots of big tournaments.” – Reuters
Original source: Spieth leads new generation - Day