Neither Tigers nor the Bears have ever failed to qualify for the play- offs but Thames Valley, who scraped through in eighth place last season, needed victory at Worthing to close on the top eight.
Worthing had lost their previous two encounters with Tigers this season but hit the first 11 points on Saturday as American James Hamilton began amassing his game-high total of 35 points.
Tigers, former National Cup and League Trophy winners, were just four points down at half-time and tied the scores on 79-79 before Gary Smith hit a three-pointer to open Worthing's match-winning lead.
Hemel and Watford Royals slipped firmly back into their losing ways at home to Derby on Saturday night, where the Storm's fifth win in their last seven games, by 108-88, lifted them to joint fifth in the League. The Royals had lost every game since the start of the season before they beat fellow strugglers Crystal Palace last weekend.
London Towers travel to Moscow today, tantalisingly in touch with Russian club Autodor Saratov but needing to secure their season's best result to overturn a five-point deficit and reach the last 16 of the European Cup.