The pair are the only players to have scored 8 hat-tricks and more than 100 goals in the competition and are also the all-time top-scorers in the Champions League Round of 16 since the stage was introduced as part of the 'knockout round' in 2003-04.
Ronaldo and Messi have had a lukewarm start to the 2019-20 Champions League, with both players scoring two goals each. The latter, however, created history with both of his strikes. The Barcelona talisman's goal against Slavia Prague in October last year made him the first player to score in 15 consecutive Champions League seasons while his effort against Borussia Dortmund in November made him the first player in competition history to score against 34 different opponents.
As Champions League action is set to resume with the Round of 16, let us compare the performances of the competition's two record scorers, under various parameters, in all Round of 16 games the duo has featured in so far.
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#1 Most goals
Messi leads the way with the most Champions League Round of 16 goals, having scored 26 in his career, while Ronaldo follows close behind with 23 goals. Both players found the back of the net in their respective Round of 16 fixtures last season and it remains to be seen if they will replicate similar form this term.
Ronaldo became the oldest player to score a hat-trick in the elite European competition as Juventus beat Atletico Madrid 3-0 on the night, and 3-2 on aggregate, to advance to the quarterfinals last year. Meanwhile, Messi's brace against Olympique Lyonnais at the Camp Nou eased Barcelona to a 5-1 aggregate win.
Ronaldo has the most Champions League Round of 16 appearances than any player, having played in 30 games while Messi follows close behind with 28 appearances. However, it is the Argentine skipper who has the better goal per game return in Round of 16 fixtures (26 goals in 28 games; 0.93 goals/game), compared to his Portuguese counterpart (23 goals in 30 games; 0.77 goals/game).
#3 No. of goal-scoring games/total games played
Messi has scored 28 goals in 15 different Round of 16 games he has played in, which results in a ratio of 53.6% goal-scoring games in this stage of the competition.
The corresponding numbers for Ronaldo are 30 goals in 16 games, with a ratio of 53.3% goal-scoring games.
#4 Longest consecutive goal-scoring run
Ronaldo wins this category hands down, scoring in 10 consecutive Champions League Round of 16 games from 2011-12 to 2015-16.
Messi has never scored in more than three consecutive games at this stage in the competition, with the most recent being during the 2016-17 season (second leg against PSG) and the 2017-18 season (both legs against Chelsea).
#5 No. of different opponents scored against
Ronaldo has met 12 different teams in the Champions League Round of 16 but is yet to score against the quartet of Porto, AC Milan, Lille, and Napoli.
Meanwhile, Messi has met 10 different teams in the same stage of the competition and has only failed to score against Liverpool in both legs of Barcelona's 2006-07 season, which coincidentally happens to be the last time the Blaugrana lost a Round of 16 fixture. The Catalan giants have since gone 12-0 in this round of the competition.
#6 Most goals in a Round of 16 tie
Messi's six goals across both legs of Barcelona's 2011-12 Round of 16 match-up with Bayer Leverkusen represents the best goal haul by a player in this stage of the Champions League. In addition, his five-goal haul in the second leg of the fixture marked the first occasion any player scored that many goals in a Champions League game.
Ronaldo's best return in a Champions League tie has also come against German opposition. The Portugal skipper scored braces for Real Madrid in both legs of their Round of 16 tie with Schalke 04 in the 2013-14 season.
Messi beats Ronaldo in 5 of 6 different parameters in this performance comparison and therefore takes the honours against the Juventus talisman.