Dele Alli's double sealed a superb 2-0 victory for Spurs at White Hart Lane, moving them up to third in the table, while ending Chelsea's hopes of a record-breaking 14th consecutive win.
It was only the second time this season that Tottenham have beaten a side in the top six, the other coming in a 2-0 victory against Manchester City in October.
They face City away in a fortnight's time, before travelling to Liverpool next month, but take on both Arsenal and Manchester United at home during the run-in.
Spurs still trail Chelsea by seven points but Vertonghen believes beating the Blues is step in the right direction.
"We are building a reputation at the Lane and it feels good to beat the big teams. It's a good sign we are progressing well," he said.
"Maybe everyone thought at the start of the season it would be close with the other teams but you see a proper top six now.
"It means you have to win against your rivals, especially at home, and we've done that twice now, beating City as well here.
"It's a good feeling and we're getting stronger and stronger."