Ferguson, 69, celebrates his 25th anniversary with a home game against former United captain Steve Bruce's Sunderland team in the Premier League on Saturday.
"He loves everything about his job," Giggs told Inside United magazine about the most successful manager in British football. "He loves watching United players, he loves seeing his players develop.
"You couldn't do what he does at his age and have the work ethic he has got if you didn't love it. His work ethic is incredible.
"We might get home from a European away game at four in the morning yet you can be pretty much guaranteed he'll be first in at training at 8am the next day and he'll be last to leave," added Giggs who made his debut under Ferguson at the age of 17.
The Welsh international has been involved in each of United's 12 Premier League title triumphs, just like Ferguson.
"The best piece of advice he's given me? To work hard," said the 37-year-old Giggs. "You can have all the qualities in the world but hard work is the key to everything.
"He has seen plenty of quality players come and go over the years but the main thing that sets great players apart from the rest is their work ethic."
Young Mexico striker Javier Hernandez is at the other end of the age scale to Giggs but he is similarly in awe of Ferguson's achievements.
"It would be a miracle in Mexico if somebody stayed in the job for 25 years," said the 23-year-old. "Sometimes a manager is only in charge for two games before they get fired.
"You can talk about all the things he has won and all the years he has been in charge but you wouldn't know it if you watched him on the bench. Every game looks like it's his first.
"He is so excited, so enthusiastic, he wants to win so much," Hernandez added. "He will never get bored of winning."
Ferguson has lifted more than 30 trophies during his time at Old Trafford but he will need to wring every ounce of talent and fighting spirit out of his squad if he is to win his 13th Premier League crown in May.
Mega rich neighbours Manchester City look the real deal this season and have already powered into a five-point lead over second-placed United at the top of the table.
City, who gave a clear sign of their strength by demolishing the champions 6-1 at Old Trafford last month, travel to promoted Queens Park Rangers in Saturday's late match.
Third-placed Newcastle United, this season's surprise package, entertain Everton on Saturday while Chelsea's under fire manager Andre Villas-Boas aims to end a sequence of two straight league defeats at Blackburn Rovers.
Chelsea, three points behind Newcastle in fourth spot, also let slip a 1-0 lead and missed a penalty when they were held to a 1-1 draw by Belgians Racing Genk in the Champions League on Tuesday.
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