Inside a promising Sunderland afternoon and the key question to be answered this week

Goalless draws tend to feel very much like an exercise in futility but this never really felt like one of these afternoons.

This was a game where two ambitious teams took each other on, always looked for the forward option and never settled for the point.

While no goals meant there may not have been a huge amount of drama, that is not the same as saying there was nothing to enjoy.

Coventry City broke through the middle of the pitch with impressive speed and quality, while there was a huge amount to praise in the way that Sunderland dug in and found ways to ask questions of their own. At the heart of all that technical play were two pleasing old-school performances at the heart of defence, Dan Ballard and Kyle McFadzean both colossal.

So after there was, unsurprisingly, a little frustration on both sides but a huge amount of mutual respect.

Both sides have made relatively solid if unspectacular starts to their Championship campaigns, enough to give their supporters hope that they have the promise to replicate last season's top-six finishes, but also clear evidence that some work is left to be done in the final stages of the transfer window.

While Coventry City most definitely have work still to do ahead of the deadline, the sales of Viktor Gyokeres and Gustavo Hamer have allowed them to reinvest and at this stage, they are probably slightly further ahead than Sunderland.

While relatively quiet here Ellis Simms is slowly finding his feet, and Haji Wright looks an excellent addition. The striker missed the key chance in this game but was a constant thorn in Sunderland's side as he exploited some tired legs and made some dangerous runs off the backline.

Two really good sides, Robins said afterwards. No doubt about that. The question is whether they can go to the next level in the weeks and months ahead.

For Sunderland, there are solid foundations but some clear issues to address. Zero points from their first two games felt like a deeply unfair return given their efforts and performance levels and so the last two games have been encouraging, results that more closely reflected what they had produced. Tony Mowbray's side are yet to face any of the relegated Premier League sides or any of those still benefiting from parachute payments, but that they have competed and at times impressed in each of their four games bodes well.

The work rate in particular was impressive here, in a rare game where they did not dominate the ball. They had to defend the box at times, press aggressively and race to cover any gaps that Coventry were able to find. While the decision not to pick Danny Batth has proved a divisive one, Ballard and Luke O'Nien more than justified Mowbray's faith. The transfer window has made this an at times unsettled club in recent weeks but the spirit that powered the side to a sixth-placed finish despite so many injuries this season remains.

Where this obvious concern is cutting edge and in depth.

It would be too simplistic to say that Sunderland didn't score purely because they didn't have a striker on the pitch; at times the delivery wasn't quite right and the frustration both on the pitch and in the dugout throughout the game spoke to that. Too many balls from promising positions were either too close to the goalkeeper, or unable to get past the first defender. And yet at the same time, the ease with which Sunderland are playing their way to the byline only makes it all the more frustrating that there are so rarely enough players in the six-yard box to exploit it.

Mowbray has said before that any striker who has something about them can come into this team and score goals: this was another day that proved it.

It was also another day that showed the depth in the squad is not quite where the head coach would ideally like it to be. Abdoullah Ba produced some good moments here and has a huge amount of talent, but he is understandably not yet at Patrick Roberts' level and his end product is firmly a work in progress. Though Sunderland's injury situation will ease as time goes by, the fragility in the squad was reflected in Mowbray naming Elliot Embleton, Jenson Seelt and Chris Rigg on his bench despite not realistically expecting any of them to feature. Hemir did, but is adapting and clearly still getting to grips with his role. At the moment Danny Batth, Alex Pritchard and Lynden Gooch are hugely important in providing genuine cover and experience, so the uncertainty over their future is a source of obvious concern for supporters.

Mowbray expressed some concern that the club might not sign another striker in the window, which had alarm bells ringing but also needs to be put into some context. He was stung last week when confident a deal would arise, only for it to fall through in the days that followed.

And given his focus in the last couple of days was on this game, that he was not aware of any major developments immediately after the game does not necessarily mean there are any.

"I know the club are very focused on what can turn this team from a good team into a very good team, and let's see what this week brings" he said.

Which gets right to the heart of it. Will this be a good Championship team or a very good Championship team? This time next week, we'll have a much better idea.