Hugo Lloris almost single-handedly prevented Villas-Boas' side from slipping to a damaging defeat against Lazio in Rome, but Spurs have a chance to restore some faith by beating the in-form Hammers in one of the most fiercely-contested derbies in the capital. Three defeats in recent weeks have seen Tottenham fall away from the top four and Caulker is keen to arrest the slump.
"It's important for us to get our form back in the league," the Tottenham defender said.
"We made a good start to it. We hit a bit of a dip in form but we're a good bunch of lads and we're working hard every day to put it right. There's no denying it's a massive game for us and we're confident we can get three points and put the season back on an upwards spiral."
Villas-Boas will once again be without a number of key players for tomorrow's game. Emmanuel Adebayor will watch from the stands as he begins a three-match suspension while long-term absentees Scott Parker, Younes Kaboul and Benoit Assou-Ekotto remain sidelined.
Playmaker Mousa Dembele made his recovery from a month-long hip injury layoff against Lazio but is unlikely to start tomorrow. "The injury is OK, but I don't think I can play all game," the Belgian said.