The form book before the game pointed to an easy win for West Ham.
Sunderland were rooted to the foot of the table with two points while the Hammers had won all three of their away games against Arsenal, Liverpool and Manchester City.
But this is the Premier League, so inevitably the Mackems found themselves 2-0 up on 22 minutes thanks to goals from Steven Fletcher and Jeremain Lens.
Lens went from hero to villain second half, getting a second yellow card to leave Dick Advocaat's side facing a challenge to hold onto their slender lead.
And minutes later Dimitri Payet, who was at fault for the second Sunderland goal, followed in Manuel Lanzini's speculative shot to tap home Costel Pantilimon's parry.
Hammers sub Nikica Jelavic could have sealed the ultimate comeback late on but was stretching at the far post and could only send his effort bobbling over the bar.
Here's how West Ham's players fared against Sunderland.
Adrian – 6
The Hammers hero was lobbed from 18 yards out by Lens for Sunderland's second but sometimes you have to hold your hands up at the quality of finish and this was one of those occasions. Didn't actually have that many shots to save throughout the game but did have a big hand in the turning point. As Fabio Borini bore down on goal at 2-0, Adrian was quick off his line and closed the angle just enough to force the striker to put his effort wide. It was a mixture of good goalkeeping and poor finishing but helped swing the momentum West Ham's way after that.
Jenkinson – 9 (Man of the match)
Back to his best here, Jenkinson showed his early season jitters were temporary with a great performance at both ends of the pitch. Getting forward and supporting the attack was such a feature of his game for the Hammers last season but he has struggled for form this time around. Although he gave away what was a very debatable free-kick which led to Sunderland's first goal on 10 minutes, was up and down all game and scored a vital goal before half-time to halve the deficit. It was his first goal for West Ham and a finish a seasoned striker would have been proud of.
Tomkins – 7
Struggled to cope with the Sunderland attack in the first half but once West Ham got themselves back in the game he tightened things up and looked more focused. Truth is, though, he will struggle to stay in the side when Angelo Ogbonna returns from injury because Bilic's side look so much stronger with the Italian international and Reid at the back.
Reid – 6
Was carrying a knock going into the game and was sold short by Payet with the pass that led to Sunderland's second. Went off injured on 66 minutes being replaced by James Collins.
Cresswell – 7
Had a very good game, getting up and down the line supporting the attack and played a neat ball to Moses which provided the space for him to create the first goal for West Ham. Continues his remarkable record of playing in every minute of every one of West Ham's Premier League games since signing from Ipswich last summer.
Moses – 6
Gets a six because he set up the first goal and looked dangerous at times but this was another performance which shows why Chelsea were happy to loan him out. Must find that consistent threat over 90 minutes but is definitely playing catch-up in terms of fitness and is some way behind having missed a lot of pre-season. Subbed before the hour.
Lanzini – 8
The diminutive Argentine continues to prove invaluable away from home for West Ham. Made the equaliser with his long range shot but was constantly probing and looking for the ball. Links with Payet very well and as alluded to by Bilic, Lanzini gives the French star the space to really hurt teams.
Kouyate – 6
Not as effective as usual and came out of a few 50-50 challenges without the ball which is very unlike the Senegal star. Not his worst game but certainly not his best. The balance of West Ham's midfield looks suspect sometimes and when Kouyate isn't running box to box and dominating they struggle to control the middle of the park.
Noble – 5
After two mistakes last time out against Norwich cost his side two goals in a 2-2 draw Noble looked off the boil once again. The skipper gave the ball away too many times, which is out of character for him but owes much to the fact he is given a lot more freedom on the ball by Bilic. Was subbed for Zarate on 79 minutes as West Ham chased a winner.
Payet – 8
He may have been at fault for the second goal but Payet's influence on this West Ham side really cannot be underestimated. He scored the second goal after starting the move out wide and following in Lanzini's shot like an expert striker. He then kept probing and should have been celebrating another assist after setting up Jelavic with a gilt-edged chance late on but the Croatian could not convert from three yards out.
Sakho – 6
Pretty anonymous throughout as Sunderland did a good job on the Senegal star and cutting the supply to him. Worked hard but did not get much service and cut a frustrated figure at times. He is one of the club's key players, though, and if they can keep him, Payet and Reid fit West Ham should win more than they lose.
Collins – 7
Came on for the injured Reid for the last half hour and showed his experience. With Sunderland going down to 10 men, Collins and Tomkins had less to do but everything that came their way from then on was dealt with comfortably.
Zarate – 6
Was brought on for the last 15 minutes as the Hammers chased the winner but could not get into the game enough to have an impact as the hosts defended doggedly.
Jelavic – 6
Was stretching for what surely would have been the winner at the far post but was not sharp enough to get there and turn the ball home instead sending it bobbling over the bar. Jelavic would get goals in this West Ham team with the number of chances they create, but he is not going to realistically play ahead of Sakho or Andy Carroll when, or more perhaps more aptly if, fit.
Subs not used: Randolph, Obiang, Antonio, Oxford