The final score was 1-1 up in the skies where a pre-match protest plane bearing the slogan “No contract #Wenger out” was followed during the game by a second aircraft trailing a message of support for Arsenal’s beleaguered manager.

Down on the ground, though, there was only more misery for Arsène Wenger. This 3-1 defeat, Arsenal’s fourth in five Premier League matches, only deepens the sense that the Frenchman’s long reign is reaching an imminent, and unhappy, end.

Champions League qualification is looking less likely by the week for a team in their worst run of form since 1995 and Arsenal will finish the weekend down in sixth place if Manchester United win at Middlesbrough tomorrow. Most worrying of all was the nature of their defeat – Arsenal were well beaten here, second-best to a more determined Albion side.

West Brom vs Arsenal player ratings Show all 23 1 /23 West Brom vs Arsenal player ratings West Brom vs Arsenal player ratings <b>West Brom:</b> Boaz Myhill – 7 out of 10 Left stranded for Giroud’s header as he was given no chance from close range. Otherwise commanded his area very well, and his good day’s work was summed up with a late save from Koscielny’s volley. 2015 Getty Images West Brom vs Arsenal player ratings Craig Dawson – 7 out of 10 Had his work cut out in the second half as Sanchez switched to the left. But he did well to reduce the threat from Gibbs and frustrated the Chilean forward late on. 2015 Getty Images West Brom vs Arsenal player ratings Jonny Evans – 7 out of 10 Showed his valuable experience as he stuck to Giroud in open play, giving the Frenchman no chance of getting a clear-cut effort on goal. West Brom vs Arsenal player ratings Jonas Olsson – 5 out of 10 At fault for Giroud’s opener as he lost his man at Özil’s free-kick. Guilty of messing around with the ball ahead of Arsenal’s penalty, though that may have had its desired effect on Cazorla. 2015 Getty Images West Brom vs Arsenal player ratings Chris Brunt – 7 out of 10 Perfect delivery gave Morrison the chance to score from his free-kick. Tried to get forward when possible, but today he knew his duty came in defence and he forced Bellerin to try and go outside him each time he attacked. 2015 Getty Images West Brom vs Arsenal player ratings James Morrison – 8 out of 10 Expertly finished with the outside of his right foot to volley home and level the scores from a Brunt free-kick. Worked his socks off to try and disrupt the Arsenal midfield axis, with a fair amount of success. 2015 Getty Images West Brom vs Arsenal player ratings Darren Fletcher – 6 out of 10 Sat quite deep to partner Yacob in shielding the back-four, although he didn’t have many stand-out moments. 2015 Getty Images West Brom vs Arsenal player ratings Claudio Yacob – 6 out of 10 Another who was fairly anonymous when it came to game-changing decisions, but he was always in position to cut out a killer ball and Tony Pulis could ask no more of him. 2015 Getty Images West Brom vs Arsenal player ratings James McClean – 8 out of 10 Fantastic run down the left before crossing into goal-mouth produced Arteta’s own-goal. He gave Bellerin plenty to think about as he drifted across the midfield at will. 2015 Getty Images West Brom vs Arsenal player ratings Stephane Sessegnon – 6 out of 10 Played in McClean for the second after committing Koscielny to pull Arsenal’s defence ragged. 2015 Getty Images West Brom vs Arsenal player ratings Solomon Rondon – 5 out of 10 Fairly anonymous and was hauled off for Saido Berahino in the second half. The England Under-21 striker looked much more of a threat. 2015 Getty Images West Brom vs Arsenal player ratings <b>Arsenal:</b> Petr Cech – 6 out of 10 Slightly off his line which allowed Morrison to volley the ball over his head, but there was little he could do for the second goal. Reaction save stopped a late Berahino effort although the whistle had already gone. 2015 Getty Images West Brom vs Arsenal player ratings Hector Bellerin – 6 out of 10 Lost Morrison for the goal as he was caught napping when the ball was airborne. Looked short on match fitness, although he was his ever keen self to work down the right in search of the equaliser. 2015 Getty Images West Brom vs Arsenal player ratings Laurent Koscielny – 5 out of 10 Still not his normal self and Wenger was right to question whether he should play him in the build-up to the match. Simple header back to Cech went for a corner, and he lost Berahino late on. 2015 The Arsenal Football Club Plc West Brom vs Arsenal player ratings Per Mertesacker – 5 out of 10 Went AWOL for the second goal which forced Arteta back into defence. Looked nervy on the ball, and still struggles to connect with attacking aerial balls. 2015 The Arsenal Football Club Plc West Brom vs Arsenal player ratings Nacho Monreal – 6 out of 10 The Spaniard didn’t press forward as much as he has recently with Gibbs in front of him sticking to the left, and that had an impact on Arsenal’s attacking threat as there were few overlaps from the left-back. Fairly solid in defence though, with little threat coming down his flank. 2015 The Arsenal Football Club Plc West Brom vs Arsenal player ratings Francis Coquelin – 5 out of 10 Lasted just 13 minutes after his own sliding tackle saw him suffer a knock to his knee. Replaced by Mikel Arteta, with disastrous consequences. 2015 Getty Images West Brom vs Arsenal player ratings Santi Cazorla – 4 out of 10 His form has deserted him recently. His passing was terrible in attacking positions, and his dreadful penalty attempt sums up Arsenal’s day. Slipped as he kicked the ball, sending it into his standing foot and over the bar. 2015 Getty Images West Brom vs Arsenal player ratings Alexis Sanchez – out of 10 Worked extremely hard but couldn’t fashion many chances for himself. One clear effort saw the ball escape his reach with the goal at his mercy. 2015 The Arsenal Football Club Plc West Brom vs Arsenal player ratings Mesut Ozil – 7 out of 10 Broke the record for consecutive assists as his floated free-kick saw Giroud head home to register a seventh straight game in which he’s set up a goal. Probed throughout and looked to be Arsenal’s creator for the equaliser – only it never came. 2015 Getty Images West Brom vs Arsenal player ratings Kieran Gibbs – 5 out of 10 Dangerous cross late in the first half went unpunished as no one in red could reach it. Not an out-and-out attacking player though and it showed, and he was replaced by Joel Campbell with half an hour to go. West Brom vs Arsenal player ratings Olivier Giroud – 6 out of 10 Emotion poured out of him before kick-off as La Marseillaise rang out, and he soon had something to shout about as he headed in Ozil’s free-kick. Booked late in the first half as Arsenal lost their way, and he faded in the second half. 2015 Getty Images West Brom vs Arsenal player ratings Mikel Arteta – 1 out of 10 Terrible introduction for injured Coquelin after 13 minutes in. Conceded the free-kick that led to Morrison’s goal – though he appeared to get a toe on the ball – before handling in an own-goal to give Baggies the lead. His nightmare outing was capped when he was injured three minutes after the break, and was replaced by Mathieu Flamini having played 36 minutes. 2015 Getty Images

Although Alexis Sanchez scored a swift equaliser from Craig Dawson’s early opening goal, Albion overpowered them in the second period with Hal Robson-Kanu scoring and Dawson adding a third.

There was audible disgruntlement among the away supporters before the final whistle with chants of “We want Wenger out” after Dawson’s third goal and a chorus of “You don’t know what you’re doing” when Wenger withdrew Alexis Sanchez for Alex Iwobi 12 minutes from time. By the end the away block of the Smethwick End was pockmarked with a number of anti-Wenger banners.

The spotlight burns intensely on Wenger but a word of credit for West Brom. If Arsenal’s defending was poor for all three Albion goals, Tony Pulis’s team have so much more to them these days than a set-piece threat and have now won eight of their last ten home league games.

Dawson picked up the Man of the Match award (Getty) (Getty Images)

Indeed the game’s first piece of action was a foretaste of the danger they carried throughout on the counterattack as left-back Allan Nyom dashed 60 yards upfield before drilling a ball across goal. Nobody was there to connect but the opening goal arrived soon enough.

Jake Livermore, newly recalled by England, won the ball in the middle of the pitch before Chris Brunt sent McLean driving away down the inside-left channel. Although Petr Cech repelled his shot, from Chadli’s ensuing corner, Dawson was allowed an unchecked run at the ball at the near post and leapt above Laurent Koscielny to nod in. Once again, Arsenal undone by a set-piece.

Robson-Kanu gave his side the lead in the second-half (Getty)

Sanchez’s equalising goal arrived two minutes and 45 seconds later. Picked out by Granit Xhaka in space on the left of the box, he stepped inside Dawson and smashed a shot into the roof of the net. Quite rightly, Dawson shot an angry glance at Chadli, a passive spectator who had switched off and left Sanchez unmarked.

Sanchez had his 18th league goal of the campaign but his influence diminished after he was caught on the right ankle by McLean in a poor challenge that earned the Albion winger a booking, and explains Wenger’s later substitution.

Alexis Sanchez shows his frustration (Getty)

And if Arsenal dominated possession, too much of it was in front of the Albion back four. There was no Mesut Ozil, the German having suffered a hamstring injury in training yesterday, and whether Ozil would have made any difference is a moot point in an Arsenal team with little spark at all.

Aaron Ramsey turned and drew a fine save from Ben Foster but Petr Cech saved equally well from a flashing Fletcher half-volley moments later. Cech’s involvement ended soon after when he limped off with a calf problem.

A '#Wenger Out' banner was flown over The Hawthorns (Getty)

The first half had featured the whir of a light aircraft’s engine and the trailing of the message “In Arsene We Trust #RespectAW” but even Wenger loyalists must have felt their doubts grow in the second period. Salomon Rondon failed to convert a superb Chris Brunt cross early in the second half.

He headed straight down the tunnel after being replaced by Robson-Kanu in the 54th minute but the substitute duly scored with his second touch, 75 seconds later.

Arsenal's fans protested throughout the defeat (Getty)

It was a scruffy goal but an instinctive finish by Robson-Kanu who rolled a first-time shot under Ospina after the goalkeeper had beaten McLean to Chadli’s chip into the box, but knocked the ball only as far as the Wales striker. Arsenal appealed in vain that McLean, standing behind Ospina, was offside and interfering with play.

Olivier Giroud came on as Arsenal chased an equaliser and it nearly came from Danny Welbeck who headed against the crossbar. Yet Albion finished the stronger. Ospina saved at the feet of Robson-Kanu and Nacho Monreal blocked Chadli’s follow-up on the goalline. Instead, Dawson was the man to finish Arsenal off with another header from a McLean corner after Alex Oxlade-Chamberlain had failed to block his run. That so-familiar Arsenal set-piece failing once again, but these days it is just one of many.

West Brom: Foster; Dawson, McAuley, Evans, Nyom; Chadli (Field 90), Fletcher, Livermore, Brunt (Yacob 73), McClean; Rondon (Robson-Kanu 54)

Subs: Myhill (gk), Olsson, Wilson, Leko