The world number one from Switzerland overwhelmed David Ferrer,one of the sport's rising young players, in less than an hour in the Qatar Open and afterwards said it was a "relief" to have Roche's help after more than a year without a coach.
Federer hardly seemed to need any of that as he won 6-1, 6-1 against the 22-year-old Spaniard who had just finished a season in the world's top 50 for the first time and is hoping to make further progress this year.
But positively though Ferrer tried to play, he was given very little chance to display the extent of his abilities, and near the end was driven by frustration into hurling his racket violently down on the court.
Despite this Federer was in no doubt that it would be an asset to have Roche's services for around ten weeks of the year.
"I have no clue what I would do [without him]," Federer said, rather surprisingly.
"It's relief that there will be help at times when I want it," he said.
The arrangement with Roche will last for one year for the time being, and represents a change of mind for the Australian, who originally turned down the opportunity to coach the world's best player when Federer asked him in February last year.
On Monday's evidence, the triple Grand Slam title holder will continue to carry all before him with or without Roche's help, although his performance suggested that a greater emphasis on net play has already been discussed between them.
Ferrer played a large number of entertaining rallies, including arguably the shot of the match, a perfectly timed and placed topspin backhand lob in the sixth game which lurched diagonally for a winner as Federer came threateningly in.
But it merely spurred Federer to further aggressive efforts, including a second break of serve in that game and an increasing ratio of attacks from the net, despite the cool, slightly slow conditions.
Federer had already set out to hit many of his groundstrokes at a pace higher than his opponent's in order to intimidate him, and the greater his lead became the more he took liberties in attempting to attack.
In closing out the first set he served and came in to the net on every point, still winning the points when he was twice obliged to make half volley pick-ups from dipping Ferrer returns.
All this convinced Ferrer, who had set out to impose his forcing ground strokes upon Federer from the start, to take a few more chances in attack, with the result that he dropped serve again in the third game of the second set after over-hitting with two ambitious forehand drives.
For a while Ferrer set out to contain a little more, but that was less successful than attack, with Federer hitting several rampant backhand winners down the line as accompaniment to his fearsome forehand and his menacing forays forward.
There were just no weaknesses in Federer's game and only occasional mistakes as he tested the limits of his assertiveness.
Federer next plays Greg Rus-edski, the former US Open finalist from Britain, who beat Jan Hernych of the Czech Republic 6-3, 7-5.
RSS