A lively Centre Court crowd, basking in warm sunshine hardly knew who to support -- the entertaining, top-ranked, 33-year-old American on his 13th visit to the championships or the plucky Briton, 458 in the world and with no real hope of advancing.
In the end they cheered both.
Agassi busied himself along the Centre Court baseline, taking the first set with a big serve in 33 minutes and the second with an ace in barely 20.
"I play with a sense of urgency," he said. "I feel like I'm always worried,"
Delgado, 26, raised his game in the third set and took advantage of momentary lapses from the eight-times Grand Slam champion to steal it with a delicate lob.
"I came up against a guy who was putting up some good resistance out there...certainly he put me to the test," the world number one said.
The Briton's joy was short-lived. Agassi broke Delgado's serve in the fifth game and finished the job with an ace, last of 16
Before packing his rackets Agassi bowed several times and blew kisses to the crowd.
"For me at this stage in my career it's quite a feeling to be out there," Agassi, whose latest Grand Slam triumph was at the Australian Open in January.
"You never really know how many chances you're going to get again. As I get older I have more capacity to embrace these moments," he added.
He said he also had to work really hard to earn such moments.
"To be number one now to me is a phenomenal accomplishment. You don't have to just play well you have to play well and a lot and that's not so easy for me anymore," he said.
With the early departure of Lleyton Hewitt in the first round on Monday, Agassi is seeded to win the tournament, but he smiled: "Just getting through the first one is the highest priority. I did that today."