West Ham are now second in the Premier League after their sixth win of the season, while Chelsea sit 15th on just 11 points from 10 games.
The hosts, who had won just one of their last 18 games against Chelsea, went ahead on 17 minutes after Dimitri Payet's corner fell to Zarate at the far post, the Argentine firing an unstoppable half-volley past Asmir Begovic from 18 yards.
West Ham should have made it 2-0 just before half-time, but Lanzini's lofted effort from Payet's through ball went over both Begovic and the bar.
Chelsea then went down to 10 men when Matic, who had earlier been booked for pulling back Cheikhou Kouyate, was given another yellow card for a needless block on the same player on the touchline.
Mourinho - who already has a suspended stadium ban hanging over him for previous indiscretions - was sent off during the break, and watched the second half from the stands at Upton Park.
Cahill dragged his side back level with a finish from six yards after Zouma had caused problems in the West Ham area from a corner, and the 10 men could have gone ahead just before Carroll's winner.
