Ollie Watkins helped fire Aston Villa to a first European quarter-final since 1998 but gave his side and England an injury scare after limping off.Watkins, named in Gareth Southgate's latest squad earlier on Thursday, headed Villa in front in the first half of a 4-0 Europa Conference League second-leg win over 10-man Ajax which sends them through to the last eight.But the striker limped off eight minutes later with a knee problem and had to watch his team-mates run riot in the second half with Leon Bailey, Jhon Duran and Moussa Diaby goals killing off the tie after last week’s goalless draw in Amsterdam.Villa and England will now wait anxiously to discover the extent of the problem, with the striker crucial to Villa’s Premier League top-four ambitions, while he was also likely to be involved in next week’s international friendlies against Brazil and Belgium.Unai Emery’s men will also have serious designs on winning Europe’s third-tier competition, having reached a first continental quarter-final since the 1997/98 UEFA Cup when they lost to Atletico Madrid.The level of opposition remaining in the competition is not of that calibre and they will be favourites to lift the silverware in Athens in May.It was a painful return to English soil for Ajax captain Jordan Henderson, who was given a frequent reminder of his ill-fated move to Saudi Arabia by taunting home fans as his side were outclassed.Just how successful Villa are between now and the end of the season may depend on the severity of the 15th-minute injury which Watkins suffered as he jarred his left knee when tackling Ajax goalkeeper Diant Ramaj.He was able to carry on after lengthy treatment and initially appeared OK when he opened the scoring 10 minutes later.The