Tottenham fans are not often grateful to Chelsea, particularly not where transfers are concerned, but on Thursday they can reflect that if Willian is not in their lineup, at least Nemanja Matic is not in Benfica's. Or at least that's the easy reading of it. Nobody would pretend that Matic is not a superb player or that he is not missed by Benfica, but the overall effect of selling him may have been beneficial.

Although the Serbia midfielder was the Portuguese league's player of the year last season, his departure seems to have done little to check their momentum: in 12 games in all competitions since Matic left, they have won 11 and drawn one. Seven points clear of Sporting with eight games remaining, the Portuguese title is all but theirs – not that the coach Jorge Jesus will be caught saying that after the way last season collapsed in the final weeks: they lost their unbeaten record and the league to Porto on the penultimate week of the season, then lost in both the Europa League and Portuguese Cup finals to end up with nothing.

More than that, the sale of Matic, plus the €45m brought in by selling the forward Rodrigo and the midfielder André Gomes to a private investment company, eased Benfica's financial troubles and enabled them to keep hold of the centre-back Ezequiel Garay, who had seemed destined for a move to Zenit. The Argentinian's partnership with Luisão has been key to their defensive solidity: only one goal conceded in those 12 games.

Just as important has been the form of Matic's replacement Ljubomir Fejsa, a 25-year-old Serbia international signed from Olympiakos last summer, who brings a similar combativeness as Matic, although perhaps not the same ball-playing ability. He has been admirably disciplined at sitting deep, almost becoming a third centre-back at times as the two full-backs push on. A muscular problem means Fejsa is a doubt for Thursday night's first leg and he could be replaced by Rúben Amorim, who took on the role in the last round. Alongside Fejsa, Enzo Pérez has been one of the revelations of the season, his tireless running helping protect the holding midfielder – a remarkable return for a player who had been largely written off when he returned to Estudiantes on loan after a serious knee injury in 2012.

On the right is another Serb, Lazar Markovic, who turned 20 last week but has already played 10 times for his country and was recently named the Portuguese league's player of the month after scoring the winner against Guimarães. He represents a major threat to Spurs, not only because of his technical ability but because of his acceleration and pace on the break – an attribute rather disguised by his nickname: "the Butterfly". If Benfica find themselves under pressure, he will be the outlet. "Markovic has great potential and can still improve," Matic said last month. "He could become one of the best players in Europe. I believe nobody will be able to stop him when he's matured. It was great to play with him."

Markovic was this week linked with a summer move to Liverpool (although if you're young, remotely talented and haven't been linked to Liverpool, your agent probably isn't doing his job properly) who had him watched in Serbia's 2-1 friendly victory over Ireland. The week before, there had been stories suggesting Chelsea and Arsenal were keen on him. It's not uncommon, of course, for promising talent to be touted round major Premier League clubs, but last summer, while he was still a Partizan player, there were strong suggestions Markovic would join Chelsea. In June, the Partizan president, Dragan Djuric, said that a deal was all but done and that Markovic would then join Benfica on loan for two years; a matter of hours later, the player signed a five-year contract with the Lisbon club. Exactly what went on remains unclear, but it's fair to assume that, at the very least, there was substantial interest from Chelsea and there remain suggestions that they have first option to sign him in summer 2015.

Like Markovic, Nicolás Gaitán, who will play on the other flank, likes to cut infield, allowing the full-backs to overlap. The Argentinian has been in sensational form recently, as borne out by his stunning goal against Belenenses earlier this month. Again, on the break, he could pose real problems.

The only real selection issue is over who will play up front. The Paraguayan forward Óscar Cardozo was out for two months with a back injury, returning at the end of January, and is still not fully fit. He's made three substitute appearances and two starts since and has totalled only 164 minutes in those five games but Jesus has hinted that he could start. It seems more probable, though, that Rodrigo will lead the line with the Brazilian Rodrigo Lima playing off him.

Like last year, Benfica find themselves fighting on multiple fronts as the run-in to the end of the season approaches. This time, the league is surely theirs. They have reached the semi-final of both both their domestic cups. But more than that, they still have Europe to dream of – and, after seven defeats in continental finals since Béla Guttmann cursed them after the 1962 European Cup success, winning any Uefa competition is a dream; 1962 was also the last time Benfica played Tottenham in a competitive fixture, a coincidence many hope will lift the curse. More practically, Spurs must beware the two inverted wingers.