Arsenal manager Unai Emery insisted his side’s Europa League semi-final against Valencia is still “50-50” despite the Gunners taking a 3-1 first leg lead to Spain.

Valencia’s bright start at the Emirates on Thursday was rewarded with Mouctar Diakhaby’s away goal.

But Alexandre Lacazette quickly turned the game around with two goals in eight first-half minutes before Pierre-Emerick Aubameyang’s late strike gave Arsenal a two-goal advantage to defend at the Mestalla on May 9.

However, Emery, who managed Valencia between 2008 and 2012, knows the tie is far from over due to Arsenal’s terrible away record this season.

“It is a good result at home, but the second leg is going to be very difficult and maybe different. I consider for both teams it is 50-50,” said Emery.

“We can be proud of the players. It is not easy to be calm and come back with that result against this team.” Arsenal are desperate not just for silverware in Emery’s first season but the guarantee of Champions League qualification for next season that winning the Europa League would bring.

“We want to win the Europa League to go straight to the Champions League but also to win a trophy,” said Lacazette.

“We want to finish in the top four in the Premier League and if we can go to Baku (for the Europa League final) it will be special.” A run of three straight Premier League defeats has left Emery’s men needing more favours from Chelsea or Tottenham to stand any chance of Champions League qualification via a top-four Premier League finish. Valencia had already missed a glorious chance to take the lead when Ezequiel Garay blazed over before Diakhaby forced the ball home at the back post for the vital away goal on 11 minutes.

Emery has been reticent to start Lacazette and Aubameyang together up front, but the game turned on one moment of magic from Arsenal’s two prolific strikers.

Lacazette played in Aubameyang and the Gabon international left his marker and Valencia goalkeeper Neto on the ground before squaring for his strike partner to roll into an empty net.

Seven minutes later, Arsenal led as terrible defending allowed Lacazette a free header from Granit Xhaka’s cross and a weak hand from Neto could not prevent the ball crossing the line.

Lacazette missed two glorious opportunities to complete his hat-trick.

Arsenal still have work to do, but they moved much closer to booking their trip to Baku when Aubameyang turned home at the back post in the final minute.

Meanwhile, Chelsea coach Maurizio Sarri defended his decision to leave Eden Hazard on the bench and said his team “deserved a trophy” after they were held to a 1-1 draw at Eintracht Frankfurt in the first leg of their Europa League semi-final on Thursday.

Pedro’s first-half equaliser gave Chelsea a potentially crucial away goal after a hard-fought clash at the Commerzbank Arena.

Sarri raised eyebrows with his decision to leave Hazard out of the starting line-up, but he said he had no choice but to rest the Belgian star.

“Eden was on the bench because he has played 10 games in a row,” said Sarri.

“It is impossible for a player to play 70 to 75 matches in a season. Sometimes they need to rest, or at least not to play for 90 minutes.

Sarri said his team had made a “mistake” in the opening 20 minutes as they struggled to deal with a determined Frankfurt in the first half.

Filip Kostic found the breakthrough for Frankfurt on 23 minutes, sending a pinpoint low cross to Luka Jovic, who ducked low to flick his header inside the far post.

Frankfurt then tried to grab control of the tie, with Sebastian Rode snapping at Chelsea’s heels in midfield and Jovic and Mijat Gacinovic lurking in wait for a chance to break.

Yet Sarri’s side eased their way patiently back into the game, and deserved to draw level when Pedro finally found the net with a well-placed strike just before half-time.

It remained a fiercely contested game after the break, and Chelsea midfielder Jorginho had to be bandaged up after a clash of heads with Rode.

Always a step ahead of Frankfurt in the second half, the visitors nearly took the lead when David Luiz struck the bar with a fizzing free-kick.

Frankfurt had a penalty appeal waved away 12 minutes from time, and both David Abraham and substitute Goncalo Paciencia came close to snatching a late winner.

Frankfurt coach Adi Huetter, meanwhile, said that his team would have to be brave when they travel to Stamford Bridge for the return leg next Thursday.

Agence France-Presse