The Blues followed up their away win at West Ham earlier in the month with a battling 2-1 victory at away to Stoke City on Saturday.
Mark Hughes' side tried to unsettle Chelsea's momentum with aggressive tactics and it looked to be working until Cahill secured all three points with a late winner.
It means Antonio Conte's men will have to suffer a mighty collapse in the final 10 League games of the campaign to miss out on the Premier League trophy. 21 points from their finals fixtures will see the title return to Stamford Bridge.
And Cahill, who has joined up with the England squad ahead of their internationals against Germany and Lithuania, is relieved to go away with the national side in such a strong position.
He said: “We can calm down because we're going into internationals now. We didn't want to go into internationals with a bad taste in our mouth.
“We spoke at the start of the month saying it's strange there's only two games this month.
“We knew if we won both what points gap we'd have and it's gone even better than we thought. That was our aim at the start of the month and we've managed to do that."
The Chelsea players and Conte celebrated madly at the final whistle, while the club's supporters chanted 'we're going to win the League'.
Cahill certainly felt it was a significant result and added: “That was up there for all of us. You saw the celebrations – everyone knows what that game meant to win.
“When the game plays out like that, and it's proven to be really difficult, a neutral might have been looking and thinking this has got draw written all over it, but we wanted to keep going.
“The importance of getting three points as opposed to one is huge. Come the end of the season that could be absolutely massive for us."
Cahill was even more delighted to get the winner having given away a penalty for Stoke's equaliser in the first half.
Referee Anthony Taylor penalised the centre half for a slight push on Jonathan Walters, who then scored from the spot.
The 31-year-old reacted even more passionately than normal when he fired the ball home in the 87th minute as he jumped into the away section.
“Emotions just take over sometimes," he said. "The way the game went, collectively for the team, you've seen everyone else's response but personally for me, I thought the penalty was very soft.
“At the time I felt like I made more contact with his feet than my hand. Sometimes you get them and you don't. For me I didn't. The end of that game, you saw the reaction and how pleased I was.”