FC Barcelona's Lionel Messi, left, scores against Shakhtar Donetsk's (Photo: AP)
Messi's first half effort not only completed a resounding 6-1 aggregate success and gave him his tournament-leading ninth strike of the campaign but also moved him past the previous club mark of former star Ronaldo, who managed 47 in the 1996-97 season, his sole campaign in the Catalan club's colours.
If he can score again - and Barca's next match is against Real next weekend - he will equal the all-time Spanish record held by Real's late Hungarian legend, Ferenc Puskas, achieved in 1959-60.
Messi has blasted his 48 in only 46 matches and if Barca can now see off likely semi-final rivals Real Madrid - who must Wednesday preserve a 4-0 advantage over Tottenham in their return leg - to reach the final, then the 23-year-old will have another nine games in which to stretch his record.
Ronaldo hit his 47 goals in 49 - a total Messi matched last season.
This season the Argentine has scored nine times in ten Champions League encounters, 29 times in 28 league games, seven times in six Spanish Cup matches and three times in two Spanish Supercup games.
Messi scored two minutes before the break with a neat left-footed effort.