The Blues emerged from their trip to Sunderland on Saturday evening with just a point from a hard-fought 0-0 draw, but remain clear at the top of the table.
Manager Jose Mourinho fielded the same starting XI for the third successive game after a 2-0 league win over West Brom and Tuesday night's 5-0 Champions League demolition of Schalke in Germany, but saw them struggle to break down a committed Black Cats outfit.
Nevertheless, they emerged with a third successive clean sheet and a point, and that, in Cahill's opinion, demonstrated a new attribute.
The 28-year-old England international told Chelsea TV: "I think we are a different side to last year, not just personnel, but mentally I think we are different.
"They made it a scrap, but we matched that and managed to play our football as well
When teams sit back and get back in that shape, it's very tough
We saw that last year and this was no different.
"But in these sorts of games, if you don't get the breakthrough, it's important we don't lose the game, and it's a point away from home."
Chelsea have now put together an unbeaten run of 20 games since the start of the season, but this was the first in which they had been prevented from scoring.
They enjoyed the greater share of the possession at the Stadium of Light, particularly in the first half, but apart from Willian's 17th-minute shot, which was tipped on to the post by keeper Costel Pantilimon, and another from Branislav Ivanovic which the Romanian blocked with a foot, they created few clear-cut chances.
At the other end, defender Santiago Vergini clipped the crossbar and midfielder Adam Johnson went close twice in a late flurry as Gus Poyet threatened to guide his side to a third successive victory over the club for which he played with such distinction inside 12 months.
It proved a frustrating evening for striker Diego Costa, who escaped punishment after appearing to kick out at defender John O'Shea, but then collected his fifth booking of the campaign for catching Wes Brown with an arm as they jumped for a high ball, and he will miss Wednesday's home clash with Tottenham.
However, Cahill was pleased with another clean sheet and a point from what proved to be just as tough an assignment as he had expected before kick-off.
He said: "It was a game in which we needed to defend well
They defended well as well
It was exactly what we expected, it was a scrap of a game.
"They made it tough by, when we had possession, sitting back very deep, but they worked very hard, so credit to them, and they looked dangerous when they tried to hit us on the break, so we had to be on our toes and defend well.
"Unfortunately for us, we didn't manage to break through
If we had broken through, it's all of a sudden a different game because like we have seen before, they have to come out then and try to get the equaliser and it allows us to play a bit more.
"But credit to them, they did well and defended as a unit."
Source : PA