The second tier of European football competition, otherwise known as the UEFA Europa League, has produced some interesting battles so far. The competition recently concluded its matchday five and we are one more round of matches away from the knockout phase.The eight group leaders will directly qualify for the final 16. The other eight teams (runners-up) will have to play against the third-placed teams from the Champions League (from their respective groups) to secure a berth in the round of 16.Spanish side Real Betis and German outfit SC Freiburg have already ensured the top spot in their group, thereby qualifying for the final 16.With one round of matches left to be played, we will take a look at the four most in-form teams in the Europa League.#4 Royale Union Saint-Gilloise1. FC Union Berlin v Royale Union Saint-Gilloise: Group D - UEFA Europa LeagueBelgian team Royale Union Saint-Gilloise has impressed everyone with their football this season. They are unbeaten in the Europa League, winning four and drawing one of their five games. Royale Union Saint-Gilloise@UnionStGilloiseGROUP WINNER !! #MFFUSG65457GROUP WINNER !! 👊💥#MFFUSG https://t.co/pRXXHYOi9hUnion SG leads Group D, having scored 11 goals and conceded only six. Their Nigerian forward, Boniface Victor, is also the joint second-highest scorer in the Europa League. He is a key player for the team's success this season.#3 FreiburgSport-Club Freiburg v Olympiakos Piraeus: Group G - UEFA Europa LeagueSC Freiburg have secured qualification for the final 16 after playing some scintillating football in Europe. They have drawn one and won four games, scoring 12 goals and conceding just two.SC Freiburg@scfreiburgGuten Morgen, Achtelfinalisten! 58320Guten Morgen, Achtelfinalisten! 😍 https://t.co/prd7do1pAIThey topped the group consisting of teams like Nantes, Olympiacos, and Qarabag.#2 Real BetisReal Betis v UD Almeria - LaLiga SantanderMuch like the two teams mentioned before, Real Betis too have won four and drawing one game this season. They are one of the few sides who are unbeaten this season.Real Betis Balompié@RealBetis_enTo the last 16 of the @EuropaLeague!#EuroBetis1266🇪🇺💚😁To the last 16 of the @EuropaLeague!#EuroBetis https://t.co/y0I7DWUNKRThey have hit nine goals, conceding four and lead the group 13 points. Manuel Pellegrini's side are a strong contender to go deep into the competition this season.#1 Real SociedadGirona FC v Real Sociedad -Another La Liga side who are doing brilliantly well this season is Real Sociedad. They have a 100% win record, which includes a win against Manchester United. UEFA Europa League@EuropaLeagueReal Sociedad. Unstoppable. #UEL1050116Real Sociedad. Unstoppable. #UEL https://t.co/lt2H20RxtQThey have only conceded one goal so far, securing 15 points and scoring 10 goals. If they can carry on with their form, Sociedad stand a decent chance of wining the tournament itself!