Be not a patch on somebody/something
Definition 1 of 1
Pro Tip 1/3Comparing Quality
Use this phrase to indicate something is significantly less impressive or satisfactory. 
Her performance tonight was not a patch on her rehearsal yesterday.
Pro Tip 2/3Negative Comparison
The phrase emphasizes a negative opinion by comparing unfavorably to a known standard. 
The coffee here is not a patch on what we had in Italy.
Pro Tip 3/3Idiomatic Expression
Understanding this phrase helps grasp the informal tone often found in conversational English. 
His new song is catchy, but it's not a patch on his classic hits.