"Tin Man" featured this dialogue:
Data: "Starbase 123 has detected two D'deridex class cruisers on an intercept course. The top speed of this class cruiser is known to be less than ours. Therefore we do have some advantage."
And later, when one Romulan ship outflies the Enterprise
at warp anyway and then strafes her at impulse:
Riker: "I thought you said the Enterprise was faster than this Romulan."
Data: "In fact, we are, Commander. However-"
The first dialogue specifically refers to the interstellar speed of the Romulans. The second isn't quite so explicit, but the context is clear anyway: Riker is incredulous that the Romulans could have arrived at Beta Stromgren so quickly, not that they would be flying at high impulse speed in the actual engagement.
Interesting how the Romulan ships are "cruisers" to Data, but "warbirds" to Worf...