Viktor Gyokeres struggled during his debut for Arsenal against Manchester United on Sunday. His lacklustre performance was made even more glaring when compared to Mika Biereth, a striker the Gunners sold last year for just £4million, who is now valued higher than their new Swedish forward. Last month, Gyokeres, 27, moved to the Emirates Stadium from Sporting CP in a deal worth £ 55million plus £8.5m in add-ons . Fans hailed his arrival as the final piece of the jigsaw, with Arsenal's lack of a proven goalscorer costing them dearly in recent title races. But Gyokeres' display at Old Trafford suggested otherwise. He managed just 21 touches, completed nine passes and failed to get a single shot off before being subbed off for Kai Havertz after just 60 minutes. Roy Keane criticised the Swedish international's performance, insisting he "didn't look sharp", a sentiment echoed by Daniel Sturridge . "He didn't look sharp. He had moments where he showed his physicality, but he wasn't clinical enough in the final third," Keane said after the game, with Sturridge adding: "The Premier League is a different beast. He's coming from a league where he had more time and space, and today, he was rushed into decisions." It's fair to say that there's a significant amount of pressure on Gyokeres to perform and justify the hype, especially considering Arsenal spent half the summer pursuing his signature. If Gyokeres fails to deliver, the Arsenal board may rue their decision to let Biereth go for next to nothing last summer, particularly as he is now valued at more than Gyokeres is. The London-born Dane, who currently plays for AS Monaco, is worth £64m according to CIES Football Observatory - a figure higher than the sum Arsenal shelled out for Gyokeres. Biereth was with Arsenal for three years after signing from Fulham in 2021. He netted 12 goals for the Under 21s in his debut season at the academy, matching first-team top scorer Bukayo Saka . He was included in the senior matchday squad four times - all in January 2022 - but didn't get a chance to play in any of those matches. These included the FA Cup third round loss to Nottingham Forest , both legs of the Carabao Cup semi-final defeat against Liverpool and the goalless draw with Burnley in the Premier League . However, the forward never got another opportunity. He had loan spells at RKC Waalwijk, Motherwell and Strum Graz before Arsenal decided to offload Biereth last summer. He then signed for Strum for just £4m. After finding the back of the net 14 times in 25 appearances during the first half of the 2024/25 season, Monaco decided to snap up Biereth for £13m in January. The 22-year-old maintained his impressive form into the latter part of the campaign, scoring 13 in 16 league games for his new club. Biereth was in the starting line-up for Monaco in their Ligue 1 opener on Saturday but failed to score as he was substituted in the 80th minute in his side's 3-1 victory against Le Havre. Monaco, who are back in the Champions League , face Lille in their next league game on Sunday. Join our new WhatsApp community and receive your daily dose of Mirror Football content. We also treat our community members to special offers, promotions, and adverts from us and our partners. If you don't like our community, you can check out any time you like. If you're curious, you can read our Privacy Notice.