Late goals gave Liverpool a 2-0 home win over 10-man Inter Milan, while Roma came from behind to beat Real Madrid 2-1 as the Champions League resumed after its nine-week winter break on Tuesday.
In the night's other last 16 first-leg matches, Germany's Schalke beat 2004 winners Porto 1-0 in Gelsenkirchen while Chelsea were held to a 0-0 draw at Greek champions Olympiakos Piraeus in Athens.
Needing a win to bounce back from Saturday's shock 2-1 FA Cup defeat to Championship (second division) Barnsley, Liverpool pinned back Inter from the start and got the result they wanted thanks to strikes from Dirk Kuyt and Steven Gerrard.
Inter's packed defence held out in the first half after having Marco Materazzi sent off in the 30th minute for two yellow cards, but the Serie A leaders cracked in the closing stages after relentless pressure from the 2005 winners.
Inter coach Roberto Mancini acknowledged Materazzi's dismissal for two fouls on Liverpool striker Fernando Torres had put paid to his team's hopes of getting a better result ahead of the return leg at the San Siro.
"With 10 it's very hard," he told Sky Sport. "The players made the most of it on the field and unfortunately the last five minutes were fatal," he said.
Torres twice came close and Liverpool had a strong penalty claim waved away before Dutchman Kuyt finally broke the deadlock in the 85th minute with a downward volley that bounced wickedly over the outstretched arms of keeper Julio Cesar.
Gerrard delighted the Anfield faithful in the final minute of regular time when he drilled in a crisp low shot from 25 metres that beat Cesar all the way at the far post.
PERFECT START
Roma captain Francesco Totti had a hand in both Roma goals as the Italian side registered their first home win over Real Madrid in Europe's premier club competition after three successive defeats at the Olympic Stadium.
Raul gave nine-time European champions Real a perfect start in the eighth minute when he turned in a speculative shot by Guti after Arjen Robben's darting run and cross from the left.
David Pizarro drew Roma level midway through the first half with a deflected effort after Totti had fed Mancini and the Brazilian played the ball into his path.
Mancini grabbed the winner shortly before the hour with a cool finish, having rounded the keeper after Totti won a loose ball in midfield and put him through.
In Athens, Chelsea held on to a goalless draw in the cauldron of the Karaiskakis stadium with captain John Terry and England midfielder Frank Lampard starting on the bench.
Roared on by their frenetic fans, Olympiakos often came forward but it was Avram Grant's side that looked more likely to score on the break as both sides created few clear-cut chances.
"The result is okay," Grant told reporters. "We always want to win but a draw away is OK," he said.
"The performance though was a bit disappointing, we only created two chances. But it is difficult to play here, they have good supporters and Olympiakos are very well organised, tactically very good."
