United, who enquired about the £20million-rated Argentine in December, were among top clubs whose scouts saw the winger hit a hat-trick in a 4-0 win over Leixoes.
Meanwhile, United owners the Glazer family have reiterated the club are not for sale after fresh enquiries from city financiers the Red Knights. Ttheir statement comes after United remained behind Real Madrid in the latest Deloitte Football Money League.
On fire: Benfica's Angel di Maria hit a brilliant hat-trick in the 4-0 win over Leixoes
The amount of cash generated by United still increased by £21.4m to £278.5m in 2008-09 and Deloitte's Alan Sswitzer said: 'Tthe only area there has been a decline is in corporate hospitality.'
Manchester United veteran Gary Neville not ready to commit to another season at Old TraffordMichael Owen happy at Old Trafford as Manchester United striker sets sights on silverwareMANCHESTER UNITED FC