It was the start that dreams are made of for the 19-year-old, already a Republic of Ireland international and now learning to live with being Britain's most expensive teenager following his transfer from Wolverhampton Wanderers last Thursday.
He can barely know his new team-mates yet, but he knows how to score and one demonstration in each half was enough to see off Derby. Substituted six minutes from time, he left to an ovation.
Leading it was Gordon Strachan, a manager unable to resist a gentle swipe at Sir Alex Ferguson, with whom he is already not speaking as a consequence of the Manchester United manager's autobiography, and who mockingly said he might have paid pounds 500,000 for Keane and played him in United's reserves.
"Until last week, Robbie was seen as one of the three best young players in the country along with Michael Owen and Joe Cole," Strachan said. "Then Coventry sign him and there are question marks. Time will tell how good he is but, so far, I'm delighted."
And how Keane deserved the praise. Closely attended by one, if not two, Derby defenders, the youngster was creating a good impression even before the moment in the 44th minute that won him instant adulation.
Mustapha Hadji's floated pass towards the right flank allowed Keane to gain a yard on his marker but, even so, as he bore down on the Derby goal, his route appeared blocked. However, after making Jacob Laursen turn one way and then another inside the box, he surprised Mart Poom with a hard, low shot. It defied the tight angle to ricochet off the goalkeeper's body and into the net.
Coming so close to half-time, the setback capped a dismal half for Derby, who seemed bereft of ideas. Jim Smith had already replaced Deon Burton with Mikkel Beck without noticeable improvement and, although they made more frequent incursions into Coventry territory during the second half, they were not able to exploit the pace of the recalled Dean Sturridge.
So long as Keane's opening goal stood alone in refreshing an otherwise arid contest there remained the danger it might secure only a point rather than the match. But the young Irishman, displaying the poise that has identified him as a striker of such high potential, banished any such anxiety among the fans with his second, clinching goal after 67 minutes.
This time Stephen Froggatt, who had replaced Paul Telfer, was the provider, slipping the ball wide of Spencer Prior to release his new colleague on the left. Thwarted more than once by the linesman's flag, Keane looked across to ensure he had not transgressed again. Satisfied he could proceed, he expertly rounded Poom and rolled the ball home.