Dilshan scored 76 off 58 balls while De Villiers notched the second fastest IPL half-century with 59 off just 23 balls for their 122-run stand for the fourth-wicket as Royal Challengers posted a mammoth total of 189 for three. De Villiers was also adjudged as Man of the Match for his whirlwind knock.
In reply, Rajasthan Royals could manage only 143 for seven despite skipper Rahul Dravid's fighting 58 off 42 balls and they suffered their first loss at home in the season.
The Royals failed to counter the left-arm spin of K.P. Apanna, who finished with four for 19 while young pacer Harshal Patel bagged two for 32. Royal Challengers skipper Daniel Vettori also bowled miserly giving away 20 runs from his four overs.
Royals got off to a very good start with Dravid in sparkling form but introduction of Apanna did the trick for the visitors, removing the Royals top-order, which has been in great form in the season.
Apanna first struck to remove leading run getter Ajinkya Rahane (13). He then struck thrice in his two overs to remove Owais Shah (10), Shreevats Goswami (1) and Dravid as Rajasthan Royals slumped from 80-1 to 91-4.
Dravid's wicket spelt the end of Rajasthan's resistance, as wickets fell at regular intervals. Besides the veteran, no other batsmen looked comfortable at the crease.
Earlier, Royal Challengers put into bat, made a sluggish start as explosive West Indian opener Chris Gayle, who had to fall back to No.4 position, couldn't open the innings since he fell ill just before the start of the match.
Virat Kohli (16), promoted up to open the innings with Dilshan, continued his bad run of form, as he holed out to Brad Hodge in deep cover in his attempt to hit out pacer Pankaj Singh.
Australians veteran left-arm spinner Brad Hogg (2-39) struck in his consecutive overs to get rid of Mayank Agarwal (15) and Gayle (6) as Royal Challengers were reduced to 67 for three in 12th over.
But Dilshan and De Villiers smashed the Rajasthan Royals bowlers to all part of the ground in the last eight overs scoring 114 runs.
Dilshan, who looked completely out of sorts early, grew in confidence while batting with De Villiers. The South African, particularly was in a destructive mood carting the Rajasthan bowing all around the ground.
Dilshan too came into his own at the end and unleashed his repertoire of shots as the Rajasthan bowlers and fielders looked completely stunned by the onslaught.