Ninety minutes later with a 4-0 victory over relegation-threatened Norwich City safely wrapped up, the home fans were able to digest what they had seen - a glimpse of the future as well as a snapshot of the past.
The shackles of the sacked David Moyes's cautious regime had been cast off and United's players, who looked clueless in a 2-0 defeat at Everton the previous weekend, played with freedom and confidence - just as they did under former boss Alex Ferguson.
The 40-year-old Giggs, after 962 appearances for the club and 25 major trophies, arguably understands better than anyone what made United such fearsome opponents under the fiery Scot.
And, like Ferguson, Giggs did not shy away from the big decisions.
"I didn't sleep last night. Leaving the likes of Juan Mata out of the starting XI was difficult and a position I've never been in before," Giggs told Sky Sports.
"I'm also one of their team-mates. I told them all individually and some of them were upset, but they didn't sulk. You saw the reaction of Juan, he's a true pro."
United took time to get into gear and for most of the first half showed many of the failings that dogged theme under Moyes.
They lacked dynamism and pace in attack and over-played in and around the penalty area.
But from the moment Wayne Rooney opened the scoring from the penalty spot after 41 minutes, the shackles were cast off.
Rooney curled in a superb second goal minutes after the restart before Mata came on to grab two poacher's goals.
"I reminded the players the tempo needed to be quicker at halftime and they reacted well to that," Giggs added.
"I enjoyed it. 4-0 is a dream day for us, I'm really pleased with the performance. It's good to end the day as we did; scoring goals and creating chances."
With media reports suggesting United have already agreed to bring in Netherlands coach Louis Van Gaal in the close season, a claim denied by the club, Giggs probably does not see his future at the helm beyond the end of the current campaign.
The job may have come too soon for the Welshman, who has proved at times this season that he can still be among United's better players.
In the few days that Giggs has been in charge, however, he has shown that he has many of the tools required to succeed in management.
"I'm not thinking about anything other than these four games. My next job is to get the players ready for Sunderland (next Saturday)," he said.
"I could have played two teams because the response of the players has been brilliant. I trust them all. I wanted experience in the team today because I knew it would be emotionally charged and they didn't let me down.
"All of us have let ourselves down this year, we haven't played to the quality we are capable of but we did that today. The standards they set today, they need to keep for Sunderland.
Asked if he would be playing for United again, Giggs added: "I've not had time to train this week but I'll train again on Monday and I can't wait to get back on the pitch."
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