Manchester United
After exiting the Champions League at the last 16 stage last season, who poses the early threats to United in 2013? (Reuters)

IB Times UK takes a look at the players who could pose a threat to Manchester United's efforts to escape Group A ahead of the opening fixtures of the 2013/14 Champions League.

Bernard - Shakhtar Donetsk

After winning the Copa Libertadores with Atletico Miniero this summer, another of Brazil's prodigious talents has chosen to make the move to Europe. But despite the overtures of Arsenal, Tottenham Hotspur and Porto, 21-year-old Bernard has followed a path taken by an ever-increasing number of young Brazilians and made his move to Ukraine, where the presence of Shakhtar has long been dominant, and is now beginning to rear its head in Europe.

Costing the club €25m, Bernard arrived at the club along with fellow Brazil international Fred, but has not yet been fully unleashed in his domestic division having only joined the club a week into August. The youngster has featured in one of the four of Shakhtar's games since his arrival and will be eager to display the talent that has seen him draw comparisons with his compatriot Kaka on the biggest stage.

Manager Mircea Lucescu may exercise some caution in introducing his starlet to the extremes of European football, but for a player who helped his club to an first Copa Libertadores triumph in front of 60,000 just shy of two months ago, the diminutive midfielder is no stranger to the big occasion.

Shakhtar Donetsk's previous best finish: Quarter Finals (2011)

Brazilian prodigy Bernard has arrived in Europe. (Reuters)

Antoine Griezmann - Real Sociedad

The Frenchman was one of the key figures in Real's remarkable fourth place finish last season, but the Basque club's hopes of qualification for the group stages of this tournament encountered a seemingly troubling stumbling block after being drawn against former Champions League regulars Lyon in the qualifying stages. A 4-0 aggregate win notable for Griezmann's stunning overhead kick confirmed a rather simple progression, however.

The 22-year-old is at his most dangerous in a more advanced role than a wide position these days, as evident from his 11 La Liga goals last campaign, finishing as the club's third top scorer in a magnificent season for the club having only returned to the top flight in 2010. Operating alongside Xabi Prieto and David Zurutuza behind former Arsenal man Carlos Vela, Real Sociedad boast a quick and increasingly lethal attack capable of catching most teams on the break.

Real Sociedad's previous best finish: Last 16 (2004)

Antoine Griezmann
The Frenchman may now sport a bleach blonde bonce, but remains as dangerous as ever in attack. (Reuters)

Song Heung-Min - Bayer Leverkusen

Andre Schurrle's move to Chelsea instigated Bayer's efforts to sign Son from Hamburg this summer, in hope that the South Korean could fill the void left by the man who struck 16 goals for the club last season. With 13 goals of his own in the 2012/13 campaign and having already opened his account for his new club, Son is hopeful of being the man capable of fulfilling that role. After being heavily linked with a move to Tottenham over the past year, Son is now integral to Bayer's renewed efforts in Europe. After a debut goal against Freiberg in the Bundesliga got the 21-year-old up and running, Bayer manager Sami Hyypia will be hoping the South Korean and striker Stefan Kießling can deliver a blow to his old enemy at Old Trafford on Tuesday.

Bayer Leverkusen's previous best finish: Finalists (2002)

Son Heung-Min