The Whites took the lead midway through the first half via Raphinha, but an own-goal from Junior Firpo and Michail Antonio's last minute strike ensured the Hammers left Elland Road with all three points.
Speaking after the game, Leeds boss Marcelo Bielsa said: “They are two teams with different realities I don't think that we deserved to lose. But I imagine that the opponents' manager thinks that they deserved to win.
“When a team finds themselves in a good moment, they obtain these rewards and when a team accumulates negative results you don't find a lot of things that they deserve.
He continued: “Our project of play was the same. When you conserve a result you stop doing some things that are necessary to avoid losing what you have obtained. There are responses which are sometimes natural, trying to hold on to what you have got.
“We spend too much time defending and not enough time in the opponents' half and defend too close to the goalkeeper, it is likely that the opponents chances to score increase.
“A succession of bad results, the absence of points, the position in the table they are all factors that affect the morale of any team. When the performance is not negative, the recovery is more probable.”
Next up, the Whites will look to bounce back next Saturday afternoon, when they host Watford in a must-win game at Elland Road.
Take a look at the latest news round-up from the Premier League, as the build-up to the weekend's action continues:
“When a team finds themselves in a good moment, they obtain these rewards and when a team accumulates negative results you don't find a lot of things that they deserve.
5. Three sides race for Ramsey
Newcastle United, Everton and West Ham have all been credited with an interest in Juventus midfielder Aaron Ramsey, who could be allowed to leave the club on a free transfer. The ex-Arsenal star's hefty wages could prove a stumbling block for any potential suitors, however. (The Sun)
Photo: Marco Rosi
6. Hammers could move for Bayo
West Ham have been linked with a move for Clermont striker Mohamed Bayo. The Guinea international, who is valued at £10m, scored 22 goals for his side last season, and played a key role in their promotion from Ligue 2 to Ligue 1. He's been tipped to provide competition for Michail Antonio up-front. (The Sun)
Photo: JEFF PACHOUD
7. Toffees favourites to sign Aurier
Everton have been named fresh favourites to sign free agent full-back Serge Aurier, ahead of Arsenal and Barcelona. The former £23m Spurs man is still on the hunt for a new club after being released at the end of last season. (SkyBet)
Photo: Pool
8. Reds step up chase for Bissouma
Reports from Spain have suggested that Liverpool have already agreed a £40m deal for Brighton's star midfielder Yves Bissouma, ahead of the January transfer window. He was also linked with Man Utd and Arsenal over the summer. (Fichajes)
Photo: Clive Rose