Manchester United 'scout' Espanyol pair Aaron Martin and David Lopez ahead of summer

Manchester United scout Toni Lima was reportedly at Cornella El Prat Stadium during Espanyol's 1-0 victory over Alaves on Saturday (8 April) in order to run an eye over Aaron Martin and David Lopez. Martin has been linked with Real Madrid and Manchester City in recent times and Mundo Deportivo suggests Jose Mourinho's side are also monitoring his meteoric development ahead of a future move for his services.

Martin, 19, only made his debut with Espanyol's first team in October 2016 but has since proven to be one of the standout stars of this season's La Liga, having established himself as the first-choice left-back for former Watford manager Quique Sanchez Flores.

Espanyol quickly reacted to his impressive breakthrough into the first team and in January tied him down with a new long-term deal that expires in 2022, setting his release clause at €30m (£25.5m, $31.8) until the end of the season 2017-2018 and €40m from 30 June 2018.

However, last month The Sun reported Manchester City and Real Madrid are ready to battle for his services in the coming summer transfer window as both Pep Guardiola and Zinedine Zidane desperately need to improve their options at left-back.

Recent reports in Spain have claimed Real Madrid have turned their attention to Atletico Madrid starlet Theo Hernandez instead while City have been linked with Monaco's Benjamin Mendy.

However, Mundo Deportivo says Espanyol could still face a headache in keeping Martin in their ranks as he has now caught the attention of Manchester United.

The Spanish publication says United scout Lima, a former Espanyol player, has been regular at the stadium of Barcelona's neighbours to run the rule over both Martin and his versatile teammate Lopez.

Espanyol are unlikely to negotiate the departure of their stars on the cheap as the club's new Chinese owners are aiming at Champions League qualification in the future.

However, they can do little to retain their players if United agree to pay the release clauses.

Mundo Deportivo points out Lopez's clause was set at €40m following his return from Napoli during the last summer transfer window.

The 27-year-old was originally a midfielder but has excelled in the current campaign while playing at the heart of the defence.